Biological control potential of Turkish entomopathogenic nematodes against the Mediterranean fruit fly <Emphasis Type="Italic">Ceratitis capitata</Emphasis>

The entomopathogenic nematodes Steinernema weiseri, S. feltiae, S. carpocapsae and two strains of Heterorhabditis bacteriophora, isolated from Turkish soils, were evaluated against larvae of the Mediterranean fruit fly (medfly) Ceratitis capitata in plastic cups under laboratory conditions with sandy loam soil and 10% moisture level. At a rate of 100 infective juveniles (IJs)/cm², the last instar larvae of C. capitata were susceptible to the entomopathogenic nematodes: the S. feltiae 09-31 strain recovered from Aydin provided 78% mortality, whereas S. weiseri and S. carpocapsae killed 50% and 56% of the larvae, respectively. Both strains of H. bacteriophora species caused less than 50% mortality. Except for S. feltiae, the majority of infected medflies died as prepupae or pupae within the puparia. More than 90% larval mortality was recorded at 200 and 400 IJs/cm² for S. feltiae. None of the nematode isolates infected the medfly pupae within the puparia. In pot experiments containing soil, S. feltiae caused 96% and 97% mortality at 100 and 200 IJs/cm², respectively. In pot experiments with grass present, more than 94% mortality was obtained in the presence of grass roots.     

Sensitivity of caterpillars of the pine tree lappet moth Dendrolimus pini to native isolates of entomopathogenic nematodes

Abstract

The pine tree lappet moth Dendrolimus pini (Lasiocampidae) is one of the most dangerous pests of pine Pinus sylvestris stands in Central Europe. To develop biological control method of this pest, the bioassay was made to assess the sensitivity of D. pini caterpillars to native EPMs strains representing two species: Steinernema feltiae and Heterorhabditis megidis in laboratory conditions. The results showed higher activity of S. feltiae strains which parasitized 86.7 - 100% of D. pini caterpillars, compared to the 20-100% of insects parasitized by H. megidis strain. Most nematodes were found in caterpillars treated with S. feltiae (in average 40 IJs/caterpillar), the least – in individuals parasitized by H. megidis (in average IJs/caterpillar). No effect of dose and temperature on parasitizm was found with S. feltiae strains while in H. megidis increased doses resulted in higher extensity of parasitism. The results indicate higher biological activity of S. feltiae strains and advisability of their further studies in field experiments.     

Effect of rapid and gradual increase of osmotic stress on survival of entomopathogenic nematodes

The effect of rapid and gradual exposure of entomopathogenic nematodes to osmotic stresses on the induction of a dormant state was determined with the nematodeSteinernema feltiae IS-6 infective juveniles (IJs). Rapid exposure of nematodes to glycerol at concentrations of 24% and 28% (w/w) caused the nematodes to enter a dormant state which was characterized by shrinking and impeded motility of all nematodes within 8 h. However, pre-exposure to gradually increasing glycerol concentrations of 5%, 10% and 18% at 4-h intervals resulted in dormancy after 4 h exposure to 24% glycerol. The total time of exposure to glycerol solution was 16 h in gradual osmotic stress. For nematodes exposed to 24% glycerol solution either rapidly or gradually, recovery occurred after 40 min in distilled water. Infectivity of osmotically stressedS. feltiae IJs was evaluated by two criteria, insect mortality and invasion rate. The assays indicated that infectivity of nematodes desiccated by rapid and gradual osmotic stresses was similar to that of fresh nematodes. Rapid exposure ofS. carpocapsae ‘All’,S. riobravis ‘Texas’,S. glaseri ‘NI’ andHeterorhabditis bacteriophora HP88 IJs to the 24% glycerol solution resulted in dormancy within 8 h. These treatments caused mortality of 48.4% and 11.7% amongS. glaseri Nl andH. bacteriophora HP88 IJs, respectively. Similar effects were observed when these nematode species were exposed to increasing osmotic stress of 5%, 10% and 18% at 6-h intervals. Under these same conditions, mortality ofH. bacteriophora HP88 andS. glaseri Nl IJs was 27.5% and 61.8%, respectively. http://www.phytoparasitica.org posting Sept. 29, 2004.     

Evaluation of the entomopathogenic nematode Steinernema feltiae as a biological control agent of the whitefly,Bemisia tabaci

We evaluated the potential for using infective juveniles of the entomopathogenic nematode Steinernema feltiae to control the sweetpotato whitefly Bemisia tabaci B biotype on cucumber, hibiscus, and collard, under greenhouse conditions. The effects of four adjuvants (PVA, glycerol, Triton X-100, and horticultural spraying oil) on the efficiency of Steinernema feltiae in B. tabaci control were also assessed because they might increase nematode survival by reducing desiccation. The mortality of B. tabaci nymphs increased by 18, 18, and 20% on collard, hibiscus, and cucumber plants when S. feltiae concentration increased from 5000 to 15,000 infective juveniles/mL. When treated with S. feltiae (10000 infective juveniles/mL), second instar nymphs suffered greater mortality than the other instars of B. tabaci, regardless of host plant species. Mortality of B. tabaci nymphs was higher on hibiscus than on collard and cucumber plants. The use of adjuvants greatly increased infection of B. tabaci by S. feltiae. The combination of S. feltiae (10,000 infective juveniles/mL) and 1% horticultural spraying oil increased the mortality of second instar B. tabaci nymphs to 86% on collard and 90% on hibiscus, while the combination of S. feltiae and 0.1% Triton X-100 caused 83% mortality on collard and 89% on hibiscus. The potential for incorporating S. feltiae and the adjuvants in B. tabaci management is discussed.     

4种杀虫剂对甘草胭珠蚧的防治效果

甘草胭珠蚧Porphyrophora sophorae(Arch.)是人工栽培甘草的主要害虫。采用灌根、土壤处理法研究了35%吡虫啉悬浮剂、70%噻虫嗪水分散粒剂、48%毒死蜱乳油和5%毒死蜱颗粒剂4种杀虫剂对甘草胭珠蚧的防治效果。结果表明,8月中旬施药各药剂的防治效果均低于50%,但可有效降低翌年春季田间的虫口密度;6月中旬采用35%吡虫啉悬浮剂和70%噻虫嗪水分散粒剂灌根的防效可达80%以上。建议生产中可在6月中旬或之前采用灌溉后进行35%吡虫啉悬浮剂1 500倍或70%噻虫嗪水分散粒剂7 500倍液300mL/株灌根的措施防治甘草胭珠蚧。     

Entomopathogenic nematodes (Nematoda: Steinernematidae, heterorhabditidae) as control agents forParahypopta caestrum, a pest in the culture ofAsparagus officinalis

The entomopathogenic nematodes (EPNs)Steinernema feltiae (under the trade name Entonem) andHeterorhabditis bacteriophora (under the trade name Larvanem) were evaluated as potential control agents ofParahypopta caestrum, the major pest of the asparagus crop in Greece. In laboratory experiments the two nematodes provided equal insect suppression, but significant differences were found in the time it took them to kill the larvae.S. feltiae caused high levels of mortality within 24 h and the highest level at 48 h. In contrast,H. bacteriophora required 96 h to achieve the highest level of mortality. In field experiments, the nematodes provided equal insect suppression as compared with the insecticide cadusaphos and the mixture teflubenzuron +Bacillus thuringiensis var.kurstaki. No significant differences were found in the effectiveness of the insecticides used, but there were significant differences between the control and treatments. The findings showed thatS. feltiae andH. bacteriophora could be used to control the insectP. caestrum in asparagus culture. http://www.phytoparasitica.org posting Jan. 10, 2007.     

芜菁夜蛾线虫对沟眶象和臭椿沟眶象侵染力的研究

室内应用斯氏线虫3个种的5个品系,对越冬沟眶象幼虫进行侵染力比较,结果表明,施线虫后8天,芜菁夜蛾线虫A24品系和Beijing品系,可使在土壤内的幼虫死亡率分别达100％和90％,14天后Beijing品系的致死率亦达100％,其它3个品系均达90％左右;在土壤含水量为10～20％范围内,幼虫死亡率随土壤含水量的增加而递增,施线虫后5天,含水量20％的处理,幼虫死亡率达70％,而10～15％含水量中,死亡率为45～50％;线虫对沟眶象成虫的致死率很低仅15％。对为害臭椿树的沟眶象幼虫,用A24和Beijing品系进行防治,效果分别为77.3％和70.0％。     

Virulence and efficacy of different entomopathogenic nematode species against western flower thrips (Frankliniella occidentalis)

Virulence and efficacy of five species and strains of the entomopathogenic nematodes of the families Steinernematidae and Heterorhabditidae:Steinernema riobravis, Steinernema feltiae strains Ger. and UK, andHeterorhabditis bacteriophora strains HP88 and IS5, against the prepupal and pupal stages of the western flower thrips (WFT),Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), were investigated in the laboratory. Although all these nematodes controlled WFT to some extent, they differed in efficiency. The heterorhabditid nematodeH. bacteriophora strain HP88 was more specific to the soil-inhabiting WFT stages (36–49% thrips mortality). The steinernematid nematodesS. riobravis andS. feltiae strains Ger. and UK had only a slight effect (10% mortality) on prepupal and pupal populations of WFT, andH. bacteriophora strain IS5 had the least effect of all. A possible reason for such species variation is suggested and discussed.     

The influence of herbicides on the viability of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae)

Entomopathogenic nematodes (EPNs) are agents that can be used for the biological control of pests associated with pesticides in a tank mix. Compatibility studies need to be conducted to analyse which products are compatible with EPNs. The survival of infective juveniles (IJs) of four species of EPNs (Steinernema, Heterorhabditis) was determined after exposure to eight chemical herbicides. The effect of direct IJs exposure to herbicides for 1, 4 and 24 h was tested in a Petri dish at 15, 20 and 25 °C. The study showed that Steinernema kraussei was the most tolerant among the tested EPN species, while S. carpocapsae was the most sensitive to all tested herbicides. The lowest mortality of IJs was at 15 °C (19%). Our investigation showed, overall, the herbicides negatively affected EPN survival. The results confirmed that the compatibility is a species-specific characteristic, influenced by the temperature and time of exposure. Application of two different control ingredients (insecticide and herbicide) at the same time would reduce cost and time consumption in pest/weed control.     

小卷蛾斯氏线虫All品系对小菜蛾感染力测定

本文测定了小卷蛾斯氏线虫（S. carpocapsae）All品系对小菜蛾的感染力。结果表明：加入辅助剂的线虫液喷施于蔬菜叶面后,线虫的侵染率显著提高,证明黄原胶是一种很好的抗干燥物质;同时表明线虫的最适宜喷洒浓度为感染期幼虫3 000条/mL;线虫对小菜蛾3龄幼虫的侵染率最高;线虫的侵染率不会随着蔬菜上小菜蛾密度的增加而下降。     

利用昆虫病原线虫防治草菇双额岩小粪蝇

草菇双额岩小粪蝇Bifronsina bifrons是当前草菇生产中的重要害虫。本文测定了5个线虫品系在（30±0.5）℃下对草菇双额岩小粪蝇的致死率和LT50。结果表明,各线虫品系在浓度4000 IJs mL 1下的LT50范围为2.13～4.71 d,其中夜蛾斯氏线虫Steinernema feltiae SN品系对双额岩小粪蝇的毒力最大,LT50为2.13 d,侵染5 d后的致死率达86.67%。菇房施用4×106IJs.m 2S.feltiae SN品系和嗜菌异小杆线虫Heterorhabditisbacteriophora H06品系悬浮液于培养基表面6 d后,对双额岩小粪蝇的防治效果分别达到70.37%和45.68%,SN线虫对双额岩小粪蝇的防效与阿维菌素相当。     

Entomopathogenic fungi and nematodes against larvae of the chestnut weevil,Curculio elephas (Coleoptera: Curculionidae): a laboratory evaluation

Pest control in chestnut orchards is mainly achieved by chemicals, but there is growing focus on the potential use of biological control agents. The larval susceptibility of the chestnut weevil Curculio elephas L. (Coleoptera: Curculionidae) to different strains/species of entomopathogenic fungi and nematodes was evaluated in laboratory by soil cup bioassays. In the experiments with fungi, a wild strain of Metarhizium anisopliae caused the highest larval mortality (about 90%) compared with a commercial and a wild strain of Beauveria bassiana (80% and 77% respectively). Regarding nematodes, the commercial strain of Heterorhabditis bacteriophora was more effective in the control of chestnut larvae (77% insect mortality) than Steinernema carpocapsae (43%).     

昆虫病原线虫对小地老虎的致病力测定及防治效果

为探讨应用昆虫病原线虫防治小地老虎技术的可行性,采用培养皿滤纸法比较9个品系的昆虫病原线虫对小地老虎幼虫的致病力,同时通过盆栽试验验证了斯氏线虫属小卷蛾斯氏线虫Steinernema carpocapsae NC116品系、芫菁夜蛾斯氏线虫S.feltiae SF-SN品系和异小杆线虫属嗜菌异小杆线虫Heterorhabditis bacteriphora H06品系的保苗效果和防治效果,并测定了苦参碱与NC116品系混用对小地老虎3龄幼虫的联合作用效果。结果表明,NC116品系对小地老虎3龄幼虫致病力最高,其对3龄、4龄和5龄的LD50分别为2.4、7.5、和31.2条/头,表明随小地老虎幼虫龄期递增,其致病力下降。盆栽玉米苗上分别施用线虫100~200条/头时,对玉米保苗效果及对小地老虎3龄幼虫的控制效果依次为NC116H06SF-SN。0.8 mg/L苦参碱和NC116品系混用后,可使小地老虎3龄幼虫死亡率提高109.89%,二者表现增效作用。     

利用昆虫病原线虫与化学农药混用防治褐纹甘蔗象

褐纹甘蔗象是棕榈科植物和甘蔗的新入侵危险害虫。本研究利用昆虫病原线虫小卷蛾斯氏线虫All品系与毒死蜱、吡虫啉混用防治褐纹甘蔗象。将4000条／ml感染期线虫与48％毒死蜱EC（1000mg／L）、70％吡虫啉（500mg／L）混合施用于国王椰子，7d后对幼虫的防效为96％，明显优于单剂毒死蜱（68．96％）、单剂吡虫啉（0）和小卷蛾斯氏线虫（68．42％～76．52％）的防效；混剂处理7d对成虫的防效为88．89％，亦明显优于单剂毒死蜱（72％）、单剂吡虫啉（2．50％）和小卷蛾斯氏线虫（27．78％～52．63％）。     

Prospects for the use of biological control agents against Anoplophora in Europe

This review summarises the literature on the biological control of Anoplophora spp. (Coleoptera: Cerambycidae) and discusses its potential for use in Europe. Entomopathogenic fungi: Beauveria brongniartii Petch (Hypocreales: Cordycipitaceae) has already been developed into a commercial product in Japan, and fungal infection results in high mortality rates. Parasitic nematodes: Steinernema feltiae Filipjev (Rhabditida: Steinernematidae) and Steinernema carpocapsae Weiser have potential for use as biopesticides as an alternative to chemical treatments. Parasitoids: a parasitoid of Anoplophora chinensis Forster, Aprostocetus anoplophorae Delvare (Hymenoptera: Eulophidae), was discovered in Italy in 2002 and has been shown to be capable of parasitising up to 72% of A. chinensis eggs; some native European parasitoid species (e.g. Spathius erythrocephalus) also have potential to be used as biological control agents. Predators: two woodpecker (Piciformis: Picidae) species that are native to Europe, Dendrocopos major Beicki and Picus canus Gmelin, have been shown to be effective at controlling Anoplophora glabripennis Motschulsky in Chinese forests. The removal and destruction of infested and potentially infested trees is the main eradication strategy for Anoplophora spp. in Europe, but biological control agents could be used in the future to complement other management strategies, especially in locations where eradication is no longer possible. © 2014 Crown copyright. Pest Management Science © 2014 Society of Chemical Industry     

斯氏线虫对黄曲条跳甲田间种群的控制作用

在广州,深圳等多个地点的田间试验结果表明,土壤施用斯氏线虫(Steinernema carpo-capsae)Agriotis 品系的侵染期线虫悬浮液来控制黄曲条跳甲(Phyllotreta striolata)幼虫的种群数量,当线虫剂量为100万条/m~2时,线虫的寄生率为40%—70%,有效虫口密度下降38%～84%;以50万条/m~2剂量的线虫与低浓度(1∶1000)的敌百虫混合施用,对跳甲的作用效果和前一种处理所取得的效果相接近。线虫施进土壤后15—20天内对跳甲幼虫尤其是三龄幼虫种群数量控制作用较好,超过这段时间其作用明显下降。因此,在蔬菜移栽至收割期间,施用二至三次100万条/m~2剂量的线虫悬液或50万条/m~2剂量的线虫与1000倍的敌百虫混合液,对黄曲条跳甲可取得较好的防治效果。     

Association between entomopathogenic nematodes and non-synthetic insecticides for improved control of Nasutitermes spp. (Isoptera: Termitidae) in sugarcane plantations

The aim of this study was to evaluate the in vitro efficacy of the combination of entomopathogenic nematodes and non-synthetic insecticides in the control of Nasutitermes spp. (Isoptera: Termitidae). Bioassays were performed upon insect collection from areas with the high incidence of this pest. The experimental arena for insecticide assays consisted of 80-mL plastic containers with a screened cover. We tested six insecticides and the nematode species Heterorhabditidis bacteriophora RS58, Steinernema glaseri RS38, and Heterorhabditis sp. isolates AL39, AL40, AL41, AL42, AL43, AL44, AL46, and AL47, all of which were grown in last-instar larvae of Galleria mellonella L. (Lepidoptera: Pyralidae). The insecticides Codipirol®, Pure Neem Oil®, and Pyroligneous Acid Extract® caused high mortality in adults of Nasutitermes. The nematode Heterorhabditis sp. AL40 presented a median lethal concentration of 7976 infectious juveniles per adult of Nasutitermes sp. In addition, the mixture of these three non-synthetic products at a concentration of 3% caused complete mortality in Heterorhabditis sp. AL40 and S. glaseri RS38. Future trials should be encouraged in order to evaluate the field efficiency of non-synthetic insecticides mixed or not with entomopathogenic nematodes.     

昆虫病原线虫与黑色粘板配合使用对韭菜迟眼蕈蚊的防治

为探索昆虫病原线虫与色板配合使用对韭菜迟眼蕈蚊的综合防治技术,采用培养皿滤纸法比较7品系昆虫病原线虫对韭蛆3龄幼虫的致病力,盆栽法研究斯氏线虫属3品系线虫的保苗和防治效果;并通过温室和田间试验比较10种颜色粘板和3个粘板高度对迟眼蕈蚊成虫的诱集效果,研究线虫与黑色粘板配合使用对韭菜迟眼蕈蚊的防治效果。结果表明:SF-SN品系线虫对韭菜迟眼蕈蚊3龄幼虫致病力最高,LD50为60.0条/头,施用线虫剂量为200、400条/头时,其保苗和防治效果高低依次为SF-SN、All、NC116,其中施用SF-SN品系5 d,保苗效果达62.74%,防治效果达60.26%;黑色粘板诱集效果极显著高于其它色板,且下部(色板下缘离地面1 cm处)诱集成虫量最多,与中部(15 cm)、上部(30 cm)之间差异极显著。研究表明,SF-SN品系线虫主要用于防治幼虫,黑色粘板主要诱杀成虫,二者配合使用防治效果可达97.60%,能够极大地降低虫口基数。     

Screening for environmental stress-tolerant entomopathogenic nematodes virulent against cotton bollworms

A total of 27 entomopathogenic nematode (EPN) strains originally isolated from different cotton fields were characterized in laboratory experiments for their virulence, reproductive potential and environmental tolerance. The EPN strain collections included 16 Steinernema carpocapsae (SC), three Steinernema siamkayai (SS), one Steinernema monticolum (SM), and seven Heterorhabditis bacteriophora (HB). Their virulence was tested against cotton bollworms such as the American bollworm Helicoverpa armigera, the spotted bollworm Earias vittella and the cotton leafworm Spodoptera litura. Larvae of H. armigera, E. vittella and S. litura were susceptible to all the tested EPN species/strains with significant differences among EPN species/strains. The most virulent strains were APKS2 (SC), TRYH1 (HB) KKMH1 (HB) and KKMH2 (HB) on H. armigera (91.9–93.5% mortality); KKMS1 (SC), APKS2 (SC), TRYH1 (HB), KKMH1 (HB), KKMH2 (HB) and APKH1 (HB) on E. vittella (92.7% mortality); and APKS2, TRYH1, KKMH1, KKMH2 and KKMH3 on S. litura (92.7% mortality). The results of the invasion rate assay indicated that the EPN strains more virulent against the target host had greater invasion rates. In the multiplication assay, KKMH1and OCMS1 (SC) produced a greater number of infective juveniles (IJs) (32.1–32.4 x 1000 IJs/ cadaver) in Carcyra cephalonica. Test for tolerance to heat at 40°C for 2 h revealed that KKMH1, TRYH1, KKMH2, KKMS1 and APKS2 were highly tolerant (>85% survival). IJs exposed to ambient room conditions (27–29°C; 65–70% r.h.) for 2 h showed that APKS2, OCMS1 and KKMS1 were more tolerant (68–69% survival) of rapid desiccation than others. APKS2, KKMS1 and KKMH1 showed better survival (70–73%) in slow desiccation assay when exposed to 25°C with 97% r.h. for 72 h, followed by 25°C with 93% r.h. for 48 h. The H. bacteriophora KKMH1 and S. carpocapsae APKS2 performed best in nine traits out of ten tested, followed by H. bacteriophora TRYH1, which performed best for six traits. It is suggested that the EPN strains KKMH1 and APKS2 could be deployed for a cotton bollworm management program after testing their performance under field conditions.     

Laboratory and field investigations using indigenous entomopathogenic nematodes for biological control of Plutella xylostella in Kenya

This study was undertaken to determine the potential utility of entomopathogenic nematodes for management of diamondback moth (DBM) larvae in Kenya. Five Kenyan EPN isolates, Heterorhabditis indica, Steinernema karii, Steinernema weiseri, Steinernema sp. and Heterorhabditis taysearae were tested for their ability to penetrate DBM and their speed of kill (LT₅₀). Heterorhabditis indica and S. weiseri were found to have the quickest rate of kill and S. weiseri was found to have the largest proportion of nematodes penetrating. Three of the isolates, Steinernema sp. (95), S. weiseri and H. indica, were used in a field experiment to test their ability to reduce DBM populations and damage to kale. All three nematodes caused significant reductions in populations of DBM and DBM damage, with the population reductions being similar to those caused by application of Bacillus thuringiensis ssp. kurstaki. This study shows that EPNs have great potential that should be exploited in the management of DBM in Kenya.