- Introduction
- Taxonomy
- Occurrence
- New Species
- Distribution
- Biology
- Dispersal
- Virulence/Host range/Infectivity
- Temperature
- Survival and Persistence
- Tritrophic Effects
- Compatibility
- Genetic Improvement
- Bioefficiency
- Mass Production
- Formulation and Storage
- Application
- Abiotic Factors
- Biotic Factors
- Integration in IPM
- Biosafety
- Nontarget Effects
- Commercial Products
- Quality
- Techniques
- Chromosomes
- Associated Bacteria
Temperature
Abstract
1. Li-Y; Liu-Z; Zhang-G-L; Chai-F; Zong-J. 1993. The application of Steinernema feltiae agriotes against the peach fruit borer. Acta-Phytophylacica-Sinica, 20:4, 337-342.
AB: The results of application of Steinernema feltiae agriotes, an entomophilic nematode, against the peach fruit borer Carposina niponensis [C. sasakii] showed that favourable soil temperature and moisture content for attacking C. sasakii were 20-35°C and 6-15%, respectively and the fastest mortality occurred in the range 25-30°C and around 10%, which coincided with the conditions required for the larvae of C. sasakii to emerge from the soil. It is suggested that this is the critical time for applying this nematode against the pest and a suitable quantity of nematodes is 0.6-0.8 million/m2. The results of experiments at multiple locations and demonstrations showed that the control effect of this nematode is similar or somewhat better than that of chemical insecticides, and high benefits have been observed in some 200 ha of orchards in several provinces in recent years.
2. Lindegren-JE; Meyer-KF; Henneberry-TJ; Vail-PV; Jech-LJF; Valero-KA. 1993. Susceptibility of pink bollworm (Lepidoptera: Gelechiidae) soil associated stages to the entomopathogenic nematode Steinernema carpocapsae (Rhabditida: Steinernematidae). Southwestern-Entomologist, 18:2, 113-120.
AB:Soil associated stages, pupae and last-instar larvae of Pectinophora gossypiella were evaluated for susceptibility to the entomophilic nematode Steinernema carpocapsae (Mexican strain, Kapow selection). Mean mortality responses of larvae entering the soil naturally compared to larvae buried artificially (2.5 cm deep) were 99.5 and 73.4%, resp., at 15 infective juveniles/larva. The time required for nematode infection of larvae (38.0/cm2 soil surface) was 24 h or less. Larval mortality was significantly reduced at 15.6°C compared with 21.1, 26.7 and 32.2°C. Live nematodes were found in larvae at all temperatures tested except 32.2°C. Reproduction of juveniles was evident 3 days after exposure at 26.7°C. At 26.7°C, mortality of non diapause larvae was not significantly different from that of diapause larvae. Pupae were not susceptible unless injured. EPN thus have potential as a biological control agent for P. gossypiella when larvae enter the soil.
3. Yang-P; Li-SC. 1988. The effect of temperature on the development and pathogenicity of entomopathogenic nematodes. Insect-Knowledge, 25:5, 300-302.
AB:The results showed that the symbiotic bacteria, Xenorhabdus nematophilus, can grow at 18°C - 35°C and that the optimum temperature is 30°C. Steinernema feltiae can develop to adults at 12°C-30°C and the optimum temperature is 25°C; the nematodes' infecting rate rose to 81-100% at 23°-30°C. Below 12°C and over 35°C the nematodes lost their infectivity.
4. Hague-NGM; Haukeland-S; Otto-AA. 1991. Effect of temperature on the efficacy of Steinernematid nematodes. Mededelingen-van-de-Faculteit-Landbouwwetenschappen, Rijksuniversiteit-Gent. 56:3b, 1245-1251.
AB:The efficacy of 2 strains of the entomophilic nematode Steinernema carpocapsae and one of S. feltiae against the pyralid Galleria mellonella was compared using 2 techniques. The S. carpocapsae strains were very similar, but there was some indication that the UK strain was more effective at lower temperatures than the a11 strain. S. feltiae was less infective at high temperatures (30°C) but actively penetrated the insect host at lower temperatures (10°C).
5. Wright-PJ, 1992. Cool temperature reproduction of steinernematid and heterorhabditid nematodes. Journal-of-Invertebrate-Pathology, 60:2, 148-151; 15 ref.
AB:Seven steinernematid and heterorhabditid strains were evaluated for their ability to reproduce at 10°C in Galleria mellonella larvae. Steinernema feltiae strain CA had the greatest rate and amount of infective production. There were significant differences in growth rate at 10°C between 10 bacteria clones of the genus Xenorhabdus isolated from the nematodes. Clone 069 isolated from S. feltiae strain CA had the greatest rate of growth. The capacity for reproduction of the different strains was related to the growth rate of their associated Xenorhabdus clone.
6. Grewal-PS; Selvan-S; Gaugler-R. 1994. Thermal adaptation of entomopathogenic nematodes: niche breadth for infection, establishment, and reproduction. Journal-of-Thermal-Biology, 19:4, 245-253; 31 ref.
AB:The thermal niche breadths for infection, establishment, and reproduction of 12 species and strains of entomophilic nematodes collected from diverse climatic regions was determined. Steinernema riobravis infected Galleria mellonella larvae at the widest temperature range (10-39°C), whereas S. feltiae at the narrowest (8-30°C). Thermal niche breadth for establishment within hosts was the widest for S. glaseri (10-37°C) and the narrowest for S. feltiae (8-30°C). Thermal niche breadth for reproduction was widest for S. glaseri, (12-32°C) and the narrowest for S. carpocapsae (20-30°C). S. scapterisci (20-32°C), S. riobravis (20-35°C), and Steinernema sp. (20-32°C) were more adapted to warm temperature reproduction and S. feltiae to cooler temperatures (10-25°C). Although heterorhabditids are endemic to warmer climates, the upper thermal limits and temperature optima for reproduction of Heterorhabditis bacteriophora and H. megedis were cooler than that of some of the steinernematids from South America and the Caribbean. Thermal niche breadths did not differ between conspecific populations isolated from different localities, but were different for different species isolated from the same locality. It was concluded that entomophilic nematode species have well-defined thermal niches which may be unaffected by their locality.
7. Schirocki-A; Hague-NGM. 1994. The effect of temperature on the susceptibility of the black vine weevil, Otiorhynchus sulcatus to different isolates of AB:Steinernema and Heterorhabditis. Bulletin-OILB-SROP., 17:3, 61-64; 6 ref.
Temperature profiles were obtained for 2 isolates of Steinernema carpocapsae (ALL and UK) and 2 isolates of Heterorhabditis (Nemasys-H and Fightagrub) against late-instar larvae of Otiorhynchus sulcatus. Efficacy was clearly delineated for each isolate as: S. carpocapsae 14-33°C; Nemasys-H 14-28°C; and Fightagrub 14-33°C. This paper was presented at the 4th general meeting of the IOBC/WPRS Working Group 'Insect pathogens and insect parasitic nematodes' held in Zurich, Switzerland, on 5-9 September 1993.
8. Henneberry-TJ; Jech-LF; Burke-RA; Lindegren-JE 1996. Temperature effects on infection and mortality of Pectinophora gossypiella (Lepidoptera: Gelechiidae) larvae by two entomopathogenic nematode species. Environmental Entomology, 25: 1, 179-183; 13 ref.
AB:Steinernema riobravis infected larvae of Pectinophora gossypiella over a temperature range of 15.6-38.0°C. At temperatures > 21.0°C, mortality occurred in 24-72 h, but substantial mortality at 15.6°C did not occur until 2-6 days later. In some cases, temperatures of 35.6 and 38.0°C larval mortality by S. riobravis and S. carpocapsae was lower than temperatures ranging from 21.0 to 32.2°C. The adverse effects on efficacy were greater for S. carpocapsae than for S. riobravis. Temperatures of 32.2°C and higher and exposure for 48 h or more often resulted in decreased numbers of nematode-killed larvae with living nematodes, and increased numbers of dead larvae with dead or no nematodes.
9. Brown-IM; Gaugler-R. 1996. Cold tolerance of steinernematid and heterorhabditid nematodes. Journal-of-Thermal-Biology. 21: 2, 115-121; 39 ref.
AB:Nematodes survive subzero temperatures using either a freeze-avoiding or freezing-tolerant strategy. Steinernema anomali, S. feltiae and Heterorhabditis bacteriophora were all found to be freezing tolerant. The lower lethal temperatures were -22, -19 and -14°C for S. feltiae, H. bacteriophora and S. anomali, resp. Survival after prolonged freezing at -4°C was 6, 5 and 3 days for S. feltiae, H. bacteriophora and S. anomali, resp. Acclimation to lower temperatures increased freezing tolerance. The freezing tolerance of Heterorhabditis bacteriophora increased under a stepwise acclimation regime; S. feltiae acclimated better under a direct acclimation regime.
10. Molyneux-AS. 1986. Heterorhabditis spp. and Steinernema (= Neoaplectana) spp.; temperature and aspects of behavior and infectivity. Experimental-Parasitology. 1986, 62: 2, 169-180; 25 ref.
AB:The infectivity of several species/strains of Heterorhabditis and Steinernema [= Neoaplectana] for post feeding, 3rd instar larvae of Lucilia cuprina was tested in sand at various temperatures. The steinernematids were more active at lower temperatures than Heterorhabditis and parasitized L. cuprina over a greater temperature range. The temperature range of infectivity for L. cuprina differed between nematodes of the same genus and between strains of the same species. Parasitization of L. cuprina and Galleria mellonella occurred over a temperature range that was greater than that permitting development and reproduction. Different strains of the same species had different temperature limits for development and reproduction. The heterorhabditids took longer to complete their life cycle than did the steinernematids.
Long-SJ; Richardson-PN; Fenlon-JS. 2000. Influence of temperature on the infectivity of entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) to larvae and pupae of the vine weevil Otiorhynchus sulcatus (Coleoptera: Curculionidae). Nematology, 2: 3, 309-317; 30 ref.
AB:The susceptibilities of early and late instar vine weevil larvae and pupae to three species of entomopathogenic nematodes, indigenous to the UK, were tested in a series of bioassays. Steinernema kraussei (isolates L017 and L137), S. feltiae (the commercial product Nemasys(R)) and Heterorhabditis megidis (the commercial product Nemasys(R) H, reared both in vivo in Galleria mellonella larvae and in vitro), were tested at 6, 10 and 18°C for 2 weeks (early instars of Otiorhynchus sulcatus) or 3 weeks (late instars and pupae of O. sulcatus). Nematodes were applied to over 3800 larvae or pupae and there were over 400 untreated controls. Each insect was examined subsequently to determine mortality, and parasitised specimens were dissected to establish whether adult nematodes had developed. Differences in pathogenicity between H. megidis reared in vitro and in vivo were demonstrated. S. kraussei (L137) was consistently the most virulent nematode isolate at low temperatures. The results revealed a significant (P < 0.001) effect of temperature on small larvae of O. sulcatus, but also showed differential levels of mortality, not due to nematodes, for both small larvae and pupae. The use of Abbott's correction for control mortality is challenged and the validity of competing risks theory examined.
Gouge-DH; Lee-LL; Henneberry-TJ 1999. Effect of temperature and lepidopteran host species on entomopathogenic nematode (Nematoda: Steinernematidae, Heterorhabditidae) infection. Environmental-Entomology. 1999, 28: 5, 876-883; 42 ref.
AB:Late instars of Pectinophora gossypiella (Lepidoptera: Gelechiidae), Heliothis virescens (Lepidoptera: Noctuidae), Trichoplusia ni (Lepidoptera: Noctuidae), and Spodoptera exigua (Lepidoptera: Noctuidae) were incubated at 10 temperatures ranging between 9.9 and 40°C and exposed to 150 infective juvenile entomopathogenic nematodes (Nematoda: Steinernematidae; Heterorhabditidae) per larva. The number of infecting Steinernema riobrave, S. carpocapsae and Heterorhabditis bacteriophora was recorded. Temperature, nematode species and target insect all significantly affected the number of infective juvenile nematodes invading host insects. The temperature supporting the highest levels of nematode infection varied depending on insect host species. Larvae of P. gossypiella were then incubated at the same range of temperatures, and exposed to 2 dose rates (100 and 200 infective juveniles per larva) of S. riobrave, S. carpocapsae, H. bacteriophora or H. bacteriophora. Increasing nematode dosage had no effect on the temperature at which nematode infection of P. gossypiella was highest. Doubling the nematode dose rate did not result in a significant increase in the number of infective juveniles infecting larvae for the nematode species tested with the exception of S. riobrave. The optimum temperature for the control of insect targets by a nematode will vary among target species. Assuming existing nematode temperature optima and applying the same conditions to untested insect species may not result in maximum biocontrol efficacy.
Shapiro-DI; Cate-JR; Pena-J; Hunsberger-A; McCoy-CW. 1999.
Effects of temperature and host age on suppression of Diaprepes abbreviatus (Coleoptera: Curculionidae) by entomopathogenic nematodes.
Journal-of-Economic-Entomology, 92:5, 1086-1092; 35 ref.
AB:Effects of temperature and host age on the biocontrol potential of entomopathogenic nematodes against the sugarcane rootstalk borer weevil Diaprepes abbreviatus were tested under laboratory conditions. Virulence and reproductive potential were compared among 3 nematode species: Steinernema riobrave, Heterorhabditis bacteriophora and H. indicus. Assays were conducted in plastic cups filled with moist sand. Three soil temperature regimes (21, 24, and 27°C) and 5 larval ages (20, 30, 40, 50 and 100-day-old) were combined in various treatments. The larval ages were estimated to represent 4th-10th instar. Older larvae (i.e.,100-day-old) were less susceptible to nematode infection than younger larvae. Nematodes were less virulent at 21°C than at 24 or 27°C. The virulence of H. indica was greater than H. bacteriophora in 50-day-old D. abbreviatus larvae at all temperatures, and greater than the other 2 nematode species in 20-day-old larvae at 24°C. Heterorhabditis bacteriophora was more virulent than S. riobrave 20-day-old larvae (at 24°C), whereas S. riobrave was more virulent than H. bacteriophora at 21°C (in 50-day-old larvae). Reproductive potential was greatest in H. indica followed by H. bacteriophora. The high level of reproduction in Heterorhabditis species indicates a potential for nematode recycling in field applications. It is concluded that temperature and host age should be considered critical factors in determining the time of nematode application.
El-Sadawy-HA; Saleh-MME 1999. Infectivity of Egyptian and imported entomopathogenic nematodes under different temperatures. International-Journal-of-Nematology, 9: 1, 72-75; 11 ref.
AB:Six isolates of Steinernema and Heterorhabditis sp. isolated from Egyptian soil were tested for their infectivity to Galleria mellonella larvae at 15, 25 and 35°C. For comparison, 3 imported nematode species of the two genera were tested for their infectivity to the same insect under the same temperatures. At 25°C, both Egyptian and imported nematode species were comparable to each other and were highly infective to insect larvae causing up to 100% insect mortality. The Egyptian steinernematid isolates were suitable for 15°C (>80% mortality) rather than 35°C (20% mortality). In contrast, the heterorhabditid isolates were suitable for 35°C (>80% mortality) rather than 15°C (<5% mortality). These isolates seem very suitable for use in biological pest control in Egyptian newly reclaimed lands and other semitropical lands.
Westerman-PR; Zeeland-MG-van; Van-Zeeland-MG. 1994. Infectivity and pathogenicity of the insect parasitic nematodes HETERORHABDITIS spp. and STEINERNEMA spp. for Otiorhynchus sulcatus at different temperatures. Bulletin-OILB-SROP. 1994, 17: 3, 65-69.
AB:A large number of isolates of entomophilic nematodes were evaluated for their efficacy against Otiorhynchus sulcatus in strawberries at 9, 12 and 20°C. No marked differences were found between Heterorhabditis sp. and Steinernema sp. at 20°C, but the isolates responded differently to low temperatures. Three isolates (HFsel, HUk211 and S. kraussei Mr) gave almost 50% control at 90°C and, in addition to K122 and HB1'87, these isolates also performed well at 12°C. This paper was presented at the 4th general meeting of the IOBC/WPRS Working Group 'Insect pathogens and insect parasitic nematodes' held in Zurich, Switzerland, on 5-9 September 1993.
Grewal-PS; Selvan-S; Gaugler-R. 1994. Thermal adaptation of entomopathogenic nematodes: niche breadth for infection, establishment, and reproduction. Journal-of-Thermal-Biology, 19: 4, 245-253.
AB:The thermal niche breadths for infection, establishment, and reproduction of 12 species and strains of entomophilic nematodes collected from diverse climatic regions was determined. STEINERNEMA riobravis infected Galleria mellonella larvae at the widest temperature range (10-390C), whereas S. feltiae at the narrowest (8-300C). Thermal niche breadth for establishment within hosts was the widest for S. glaseri (10-37°C) and the narrowest for S. feltiae (8-30°C). Thermal niche breadth for reproduction was widest for S. glaseri, (12-32°C) and the narrowest for S. carpocapsae (20-30°C). S. scapterisci (20-32°C), S. riobravis (20- 35°C) and Steinernema sp. (20-32°C) were more adapted to warm temperature reproduction and S. feltiae to cooler temperatures (10-25°C). Although heterorhabditids are endemic to warmer climates, the upper thermal limits and temperature optima for reproduction of Heterorhabditis bacteriophora and H. megedis were cooler than that of some of the Steinernematids from South America and the Caribbean. Thermal niche breadths did not differ between conspecific populations isolated from different localities, but were different for different species isolated fom the same locality. It was concluded that entomophilic nematode species have well-defined thermal niches which may be unaffected by their locality.
Robinson-AF. 1994. Movement of five nematode species through sand subjected to natural temperature gradient fluctuations. Journal-of-Nematology. 1994, 26: 1, 46-58.
AB:Temperature gradient fluctuations that occur naturally as a result of heating and cooling of the soil surface were reproduced within 15-cm-d, 15-cm-long acrylic tubes filled with moist sand. Sunny and rainy periods during the late summer in eastern Texas were simulated. Five ecologically different nematode species were adapted to fluctuating temperatures for 20-36 hours at a simulated depth of 12.5 cm before being injected simultaneously into the centres of tubes at that depth. When heat waves were propagated horizontally to eliminate gravitational effects, the movement of Ditylenchus phyllobius, Steinernema glaseri and Heterorhabditis bacteriophora relative to the thermal surface was rapid and largely random. However, Rotylenchulus reniformis moved away from and Meloidogyne incognita moved toward the thermal surface. When heat waves were propagated upward or downward, responses to temperature were the same as when propagated horizontally, irrespective of gravity. The initial direction of movement 1.5 hours after introduction to 20-cm-long tubes at 5 depths at 5 intervals within a 24-hour cycle indicated that M. incognita moved away from and R. reniformis moved toward the temperature to which last exposed. Differences in movement of the 5 species tested relative to gravity appeared related to body length, with the smallest nematodes moving downward and the largest moving upward.
Miduturi-JS; Clercq-R-de; Casteels-H; Grisse-A-de; De-Clercq-R; De-Grisse-A. 1995. Effect of temperature on the infectivity of entomopathogenic nematodes against black vine weevil (Otiorrhynchus sulcatus F.). Parasitica. 1994, 50: 3-4, 103-108.
AB:In laboratory studies, the effect of a range of temperatures (5-30°C) on the infectivity of Heterorhabdits sp. and Steinernema carpocapsae against Otiorhynchus sulcatus was tested. An increase in temperature resulted in an increase in infectivity of both nematodes. A 100% mortality of O. sulcatus was obtained when Heterorhabditis sp. was kept at 20°C for 12 days. A maximum mortality of 65% was obtained with S. carpocapsae at 20°C and 25°C.
Menti-H; Wright-DJ; Perry-RN 2000. Infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis in relation to temperature, age and lipid content. Nematology. 2000, 2:5, 515-521; 43 ref.
AB:The infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis from Greece (GR) and the UK was compared using Galleria mellonella larvae as hosts. Dose-response tests showed that the two Steinernema populations did not differ in their establishment rates but they were more infective than H. megidis UK 211. The temperature range for infectivity was greater than that for development. However, the optimal temperature for infection and development for all populations was 23°C. Infectivity of Steinernema populations was not affected by storage for 12 weeks. However, 12 week-old H. megidis UK 211 infective juveniles (IJ) were less infective than fresh IJ. H. megidis GR showed very low establishment rates at all the doses and temperatures tested, before and after storage. The results are discussed in relation to the nematodes' climatic origin and lipid content.
Abstract
1. Li-Y; Liu-Z; Zhang-G-L; Chai-F; Zong-J. 1993. The application of Steinernema feltiae agriotes against the peach fruit borer. Acta-Phytophylacica-Sinica, 20:4, 337-342.
AB: The results of application of Steinernema feltiae agriotes, an entomophilic nematode, against the peach fruit borer Carposina niponensis [C. sasakii] showed that favourable soil temperature and moisture content for attacking C. sasakii were 20-35°C and 6-15%, respectively and the fastest mortality occurred in the range 25-30°C and around 10%, which coincided with the conditions required for the larvae of C. sasakii to emerge from the soil. It is suggested that this is the critical time for applying this nematode against the pest and a suitable quantity of nematodes is 0.6-0.8 million/m2. The results of experiments at multiple locations and demonstrations showed that the control effect of this nematode is similar or somewhat better than that of chemical insecticides, and high benefits have been observed in some 200 ha of orchards in several provinces in recent years.
2. Lindegren-JE; Meyer-KF; Henneberry-TJ; Vail-PV; Jech-LJF; Valero-KA. 1993. Susceptibility of pink bollworm (Lepidoptera: Gelechiidae) soil associated stages to the entomopathogenic nematode Steinernema carpocapsae (Rhabditida: Steinernematidae). Southwestern-Entomologist, 18:2, 113-120.
AB:Soil associated stages, pupae and last-instar larvae of Pectinophora gossypiella were evaluated for susceptibility to the entomophilic nematode Steinernema carpocapsae (Mexican strain, Kapow selection). Mean mortality responses of larvae entering the soil naturally compared to larvae buried artificially (2.5 cm deep) were 99.5 and 73.4%, resp., at 15 infective juveniles/larva. The time required for nematode infection of larvae (38.0/cm2 soil surface) was 24 h or less. Larval mortality was significantly reduced at 15.6°C compared with 21.1, 26.7 and 32.2°C. Live nematodes were found in larvae at all temperatures tested except 32.2°C. Reproduction of juveniles was evident 3 days after exposure at 26.7°C. At 26.7°C, mortality of non diapause larvae was not significantly different from that of diapause larvae. Pupae were not susceptible unless injured. EPN thus have potential as a biological control agent for P. gossypiella when larvae enter the soil.
3. Yang-P; Li-SC. 1988. The effect of temperature on the development and pathogenicity of entomopathogenic nematodes. Insect-Knowledge, 25:5, 300-302.
AB:The results showed that the symbiotic bacteria, Xenorhabdus nematophilus, can grow at 18°C - 35°C and that the optimum temperature is 30°C. Steinernema feltiae can develop to adults at 12°C-30°C and the optimum temperature is 25°C; the nematodes' infecting rate rose to 81-100% at 23°-30°C. Below 12°C and over 35°C the nematodes lost their infectivity.
4. Hague-NGM; Haukeland-S; Otto-AA. 1991. Effect of temperature on the efficacy of Steinernematid nematodes. Mededelingen-van-de-Faculteit-Landbouwwetenschappen, Rijksuniversiteit-Gent. 56:3b, 1245-1251.
AB:The efficacy of 2 strains of the entomophilic nematode Steinernema carpocapsae and one of S. feltiae against the pyralid Galleria mellonella was compared using 2 techniques. The S. carpocapsae strains were very similar, but there was some indication that the UK strain was more effective at lower temperatures than the a11 strain. S. feltiae was less infective at high temperatures (30°C) but actively penetrated the insect host at lower temperatures (10°C).
5. Wright-PJ, 1992. Cool temperature reproduction of steinernematid and heterorhabditid nematodes. Journal-of-Invertebrate-Pathology, 60:2, 148-151; 15 ref.
AB:Seven steinernematid and heterorhabditid strains were evaluated for their ability to reproduce at 10°C in Galleria mellonella larvae. Steinernema feltiae strain CA had the greatest rate and amount of infective production. There were significant differences in growth rate at 10°C between 10 bacteria clones of the genus Xenorhabdus isolated from the nematodes. Clone 069 isolated from S. feltiae strain CA had the greatest rate of growth. The capacity for reproduction of the different strains was related to the growth rate of their associated Xenorhabdus clone.
6. Grewal-PS; Selvan-S; Gaugler-R. 1994. Thermal adaptation of entomopathogenic nematodes: niche breadth for infection, establishment, and reproduction. Journal-of-Thermal-Biology, 19:4, 245-253; 31 ref.
AB:The thermal niche breadths for infection, establishment, and reproduction of 12 species and strains of entomophilic nematodes collected from diverse climatic regions was determined. Steinernema riobravis infected Galleria mellonella larvae at the widest temperature range (10-39°C), whereas S. feltiae at the narrowest (8-30°C). Thermal niche breadth for establishment within hosts was the widest for S. glaseri (10-37°C) and the narrowest for S. feltiae (8-30°C). Thermal niche breadth for reproduction was widest for S. glaseri, (12-32°C) and the narrowest for S. carpocapsae (20-30°C). S. scapterisci (20-32°C), S. riobravis (20-35°C), and Steinernema sp. (20-32°C) were more adapted to warm temperature reproduction and S. feltiae to cooler temperatures (10-25°C). Although heterorhabditids are endemic to warmer climates, the upper thermal limits and temperature optima for reproduction of Heterorhabditis bacteriophora and H. megedis were cooler than that of some of the steinernematids from South America and the Caribbean. Thermal niche breadths did not differ between conspecific populations isolated from different localities, but were different for different species isolated from the same locality. It was concluded that entomophilic nematode species have well-defined thermal niches which may be unaffected by their locality.
7. Schirocki-A; Hague-NGM. 1994. The effect of temperature on the susceptibility of the black vine weevil, Otiorhynchus sulcatus to different isolates of AB:Steinernema and Heterorhabditis. Bulletin-OILB-SROP., 17:3, 61-64; 6 ref.
Temperature profiles were obtained for 2 isolates of Steinernema carpocapsae (ALL and UK) and 2 isolates of Heterorhabditis (Nemasys-H and Fightagrub) against late-instar larvae of Otiorhynchus sulcatus. Efficacy was clearly delineated for each isolate as: S. carpocapsae 14-33°C; Nemasys-H 14-28°C; and Fightagrub 14-33°C. This paper was presented at the 4th general meeting of the IOBC/WPRS Working Group 'Insect pathogens and insect parasitic nematodes' held in Zurich, Switzerland, on 5-9 September 1993.
8. Henneberry-TJ; Jech-LF; Burke-RA; Lindegren-JE 1996. Temperature effects on infection and mortality of Pectinophora gossypiella (Lepidoptera: Gelechiidae) larvae by two entomopathogenic nematode species. Environmental Entomology, 25: 1, 179-183; 13 ref.
AB:Steinernema riobravis infected larvae of Pectinophora gossypiella over a temperature range of 15.6-38.0°C. At temperatures > 21.0°C, mortality occurred in 24-72 h, but substantial mortality at 15.6°C did not occur until 2-6 days later. In some cases, temperatures of 35.6 and 38.0°C larval mortality by S. riobravis and S. carpocapsae was lower than temperatures ranging from 21.0 to 32.2°C. The adverse effects on efficacy were greater for S. carpocapsae than for S. riobravis. Temperatures of 32.2°C and higher and exposure for 48 h or more often resulted in decreased numbers of nematode-killed larvae with living nematodes, and increased numbers of dead larvae with dead or no nematodes.
9. Brown-IM; Gaugler-R. 1996. Cold tolerance of steinernematid and heterorhabditid nematodes. Journal-of-Thermal-Biology. 21: 2, 115-121; 39 ref.
AB:Nematodes survive subzero temperatures using either a freeze-avoiding or freezing-tolerant strategy. Steinernema anomali, S. feltiae and Heterorhabditis bacteriophora were all found to be freezing tolerant. The lower lethal temperatures were -22, -19 and -14°C for S. feltiae, H. bacteriophora and S. anomali, resp. Survival after prolonged freezing at -4°C was 6, 5 and 3 days for S. feltiae, H. bacteriophora and S. anomali, resp. Acclimation to lower temperatures increased freezing tolerance. The freezing tolerance of Heterorhabditis bacteriophora increased under a stepwise acclimation regime; S. feltiae acclimated better under a direct acclimation regime.
10. Molyneux-AS. 1986. Heterorhabditis spp. and Steinernema (= Neoaplectana) spp.; temperature and aspects of behavior and infectivity. Experimental-Parasitology. 1986, 62: 2, 169-180; 25 ref.
AB:The infectivity of several species/strains of Heterorhabditis and Steinernema [= Neoaplectana] for post feeding, 3rd instar larvae of Lucilia cuprina was tested in sand at various temperatures. The steinernematids were more active at lower temperatures than Heterorhabditis and parasitized L. cuprina over a greater temperature range. The temperature range of infectivity for L. cuprina differed between nematodes of the same genus and between strains of the same species. Parasitization of L. cuprina and Galleria mellonella occurred over a temperature range that was greater than that permitting development and reproduction. Different strains of the same species had different temperature limits for development and reproduction. The heterorhabditids took longer to complete their life cycle than did the steinernematids.
Long-SJ; Richardson-PN; Fenlon-JS. 2000. Influence of temperature on the infectivity of entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) to larvae and pupae of the vine weevil Otiorhynchus sulcatus (Coleoptera: Curculionidae). Nematology, 2: 3, 309-317; 30 ref.
AB:The susceptibilities of early and late instar vine weevil larvae and pupae to three species of entomopathogenic nematodes, indigenous to the UK, were tested in a series of bioassays. Steinernema kraussei (isolates L017 and L137), S. feltiae (the commercial product Nemasys(R)) and Heterorhabditis megidis (the commercial product Nemasys(R) H, reared both in vivo in Galleria mellonella larvae and in vitro), were tested at 6, 10 and 18°C for 2 weeks (early instars of Otiorhynchus sulcatus) or 3 weeks (late instars and pupae of O. sulcatus). Nematodes were applied to over 3800 larvae or pupae and there were over 400 untreated controls. Each insect was examined subsequently to determine mortality, and parasitised specimens were dissected to establish whether adult nematodes had developed. Differences in pathogenicity between H. megidis reared in vitro and in vivo were demonstrated. S. kraussei (L137) was consistently the most virulent nematode isolate at low temperatures. The results revealed a significant (P < 0.001) effect of temperature on small larvae of O. sulcatus, but also showed differential levels of mortality, not due to nematodes, for both small larvae and pupae. The use of Abbott's correction for control mortality is challenged and the validity of competing risks theory examined.
Gouge-DH; Lee-LL; Henneberry-TJ 1999. Effect of temperature and lepidopteran host species on entomopathogenic nematode (Nematoda: Steinernematidae, Heterorhabditidae) infection. Environmental-Entomology. 1999, 28: 5, 876-883; 42 ref.
AB:Late instars of Pectinophora gossypiella (Lepidoptera: Gelechiidae), Heliothis virescens (Lepidoptera: Noctuidae), Trichoplusia ni (Lepidoptera: Noctuidae), and Spodoptera exigua (Lepidoptera: Noctuidae) were incubated at 10 temperatures ranging between 9.9 and 40°C and exposed to 150 infective juvenile entomopathogenic nematodes (Nematoda: Steinernematidae; Heterorhabditidae) per larva. The number of infecting Steinernema riobrave, S. carpocapsae and Heterorhabditis bacteriophora was recorded. Temperature, nematode species and target insect all significantly affected the number of infective juvenile nematodes invading host insects. The temperature supporting the highest levels of nematode infection varied depending on insect host species. Larvae of P. gossypiella were then incubated at the same range of temperatures, and exposed to 2 dose rates (100 and 200 infective juveniles per larva) of S. riobrave, S. carpocapsae, H. bacteriophora or H. bacteriophora. Increasing nematode dosage had no effect on the temperature at which nematode infection of P. gossypiella was highest. Doubling the nematode dose rate did not result in a significant increase in the number of infective juveniles infecting larvae for the nematode species tested with the exception of S. riobrave. The optimum temperature for the control of insect targets by a nematode will vary among target species. Assuming existing nematode temperature optima and applying the same conditions to untested insect species may not result in maximum biocontrol efficacy.
Shapiro-DI; Cate-JR; Pena-J; Hunsberger-A; McCoy-CW. 1999.
Effects of temperature and host age on suppression of Diaprepes abbreviatus (Coleoptera: Curculionidae) by entomopathogenic nematodes.
Journal-of-Economic-Entomology, 92:5, 1086-1092; 35 ref.
AB:Effects of temperature and host age on the biocontrol potential of entomopathogenic nematodes against the sugarcane rootstalk borer weevil Diaprepes abbreviatus were tested under laboratory conditions. Virulence and reproductive potential were compared among 3 nematode species: Steinernema riobrave, Heterorhabditis bacteriophora and H. indicus. Assays were conducted in plastic cups filled with moist sand. Three soil temperature regimes (21, 24, and 27°C) and 5 larval ages (20, 30, 40, 50 and 100-day-old) were combined in various treatments. The larval ages were estimated to represent 4th-10th instar. Older larvae (i.e.,100-day-old) were less susceptible to nematode infection than younger larvae. Nematodes were less virulent at 21°C than at 24 or 27°C. The virulence of H. indica was greater than H. bacteriophora in 50-day-old D. abbreviatus larvae at all temperatures, and greater than the other 2 nematode species in 20-day-old larvae at 24°C. Heterorhabditis bacteriophora was more virulent than S. riobrave 20-day-old larvae (at 24°C), whereas S. riobrave was more virulent than H. bacteriophora at 21°C (in 50-day-old larvae). Reproductive potential was greatest in H. indica followed by H. bacteriophora. The high level of reproduction in Heterorhabditis species indicates a potential for nematode recycling in field applications. It is concluded that temperature and host age should be considered critical factors in determining the time of nematode application.
El-Sadawy-HA; Saleh-MME 1999. Infectivity of Egyptian and imported entomopathogenic nematodes under different temperatures. International-Journal-of-Nematology, 9: 1, 72-75; 11 ref.
AB:Six isolates of Steinernema and Heterorhabditis sp. isolated from Egyptian soil were tested for their infectivity to Galleria mellonella larvae at 15, 25 and 35°C. For comparison, 3 imported nematode species of the two genera were tested for their infectivity to the same insect under the same temperatures. At 25°C, both Egyptian and imported nematode species were comparable to each other and were highly infective to insect larvae causing up to 100% insect mortality. The Egyptian steinernematid isolates were suitable for 15°C (>80% mortality) rather than 35°C (20% mortality). In contrast, the heterorhabditid isolates were suitable for 35°C (>80% mortality) rather than 15°C (<5% mortality). These isolates seem very suitable for use in biological pest control in Egyptian newly reclaimed lands and other semitropical lands.
Westerman-PR; Zeeland-MG-van; Van-Zeeland-MG. 1994. Infectivity and pathogenicity of the insect parasitic nematodes HETERORHABDITIS spp. and STEINERNEMA spp. for Otiorhynchus sulcatus at different temperatures. Bulletin-OILB-SROP. 1994, 17: 3, 65-69.
AB:A large number of isolates of entomophilic nematodes were evaluated for their efficacy against Otiorhynchus sulcatus in strawberries at 9, 12 and 20°C. No marked differences were found between Heterorhabditis sp. and Steinernema sp. at 20°C, but the isolates responded differently to low temperatures. Three isolates (HFsel, HUk211 and S. kraussei Mr) gave almost 50% control at 90°C and, in addition to K122 and HB1'87, these isolates also performed well at 12°C. This paper was presented at the 4th general meeting of the IOBC/WPRS Working Group 'Insect pathogens and insect parasitic nematodes' held in Zurich, Switzerland, on 5-9 September 1993.
Grewal-PS; Selvan-S; Gaugler-R. 1994. Thermal adaptation of entomopathogenic nematodes: niche breadth for infection, establishment, and reproduction. Journal-of-Thermal-Biology, 19: 4, 245-253.
AB:The thermal niche breadths for infection, establishment, and reproduction of 12 species and strains of entomophilic nematodes collected from diverse climatic regions was determined. STEINERNEMA riobravis infected Galleria mellonella larvae at the widest temperature range (10-390C), whereas S. feltiae at the narrowest (8-300C). Thermal niche breadth for establishment within hosts was the widest for S. glaseri (10-37°C) and the narrowest for S. feltiae (8-30°C). Thermal niche breadth for reproduction was widest for S. glaseri, (12-32°C) and the narrowest for S. carpocapsae (20-30°C). S. scapterisci (20-32°C), S. riobravis (20- 35°C) and Steinernema sp. (20-32°C) were more adapted to warm temperature reproduction and S. feltiae to cooler temperatures (10-25°C). Although heterorhabditids are endemic to warmer climates, the upper thermal limits and temperature optima for reproduction of Heterorhabditis bacteriophora and H. megedis were cooler than that of some of the Steinernematids from South America and the Caribbean. Thermal niche breadths did not differ between conspecific populations isolated from different localities, but were different for different species isolated fom the same locality. It was concluded that entomophilic nematode species have well-defined thermal niches which may be unaffected by their locality.
Robinson-AF. 1994. Movement of five nematode species through sand subjected to natural temperature gradient fluctuations. Journal-of-Nematology. 1994, 26: 1, 46-58.
AB:Temperature gradient fluctuations that occur naturally as a result of heating and cooling of the soil surface were reproduced within 15-cm-d, 15-cm-long acrylic tubes filled with moist sand. Sunny and rainy periods during the late summer in eastern Texas were simulated. Five ecologically different nematode species were adapted to fluctuating temperatures for 20-36 hours at a simulated depth of 12.5 cm before being injected simultaneously into the centres of tubes at that depth. When heat waves were propagated horizontally to eliminate gravitational effects, the movement of Ditylenchus phyllobius, Steinernema glaseri and Heterorhabditis bacteriophora relative to the thermal surface was rapid and largely random. However, Rotylenchulus reniformis moved away from and Meloidogyne incognita moved toward the thermal surface. When heat waves were propagated upward or downward, responses to temperature were the same as when propagated horizontally, irrespective of gravity. The initial direction of movement 1.5 hours after introduction to 20-cm-long tubes at 5 depths at 5 intervals within a 24-hour cycle indicated that M. incognita moved away from and R. reniformis moved toward the temperature to which last exposed. Differences in movement of the 5 species tested relative to gravity appeared related to body length, with the smallest nematodes moving downward and the largest moving upward.
Miduturi-JS; Clercq-R-de; Casteels-H; Grisse-A-de; De-Clercq-R; De-Grisse-A. 1995. Effect of temperature on the infectivity of entomopathogenic nematodes against black vine weevil (Otiorrhynchus sulcatus F.). Parasitica. 1994, 50: 3-4, 103-108.
AB:In laboratory studies, the effect of a range of temperatures (5-30°C) on the infectivity of Heterorhabdits sp. and Steinernema carpocapsae against Otiorhynchus sulcatus was tested. An increase in temperature resulted in an increase in infectivity of both nematodes. A 100% mortality of O. sulcatus was obtained when Heterorhabditis sp. was kept at 20°C for 12 days. A maximum mortality of 65% was obtained with S. carpocapsae at 20°C and 25°C.
Menti-H; Wright-DJ; Perry-RN 2000. Infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis in relation to temperature, age and lipid content. Nematology. 2000, 2:5, 515-521; 43 ref.
AB:The infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis from Greece (GR) and the UK was compared using Galleria mellonella larvae as hosts. Dose-response tests showed that the two Steinernema populations did not differ in their establishment rates but they were more infective than H. megidis UK 211. The temperature range for infectivity was greater than that for development. However, the optimal temperature for infection and development for all populations was 23°C. Infectivity of Steinernema populations was not affected by storage for 12 weeks. However, 12 week-old H. megidis UK 211 infective juveniles (IJ) were less infective than fresh IJ. H. megidis GR showed very low establishment rates at all the doses and temperatures tested, before and after storage. The results are discussed in relation to the nematodes' climatic origin and lipid content.