Wolbachia is a symbiotic bacterium that alters reproductive behavior of numerous arthropods. It is the most advanced way to study phytogeny and classification based on sequences of the wsp gene. The presence of Wolbac...Wolbachia is a symbiotic bacterium that alters reproductive behavior of numerous arthropods. It is the most advanced way to study phytogeny and classification based on sequences of the wsp gene. The presence of Wolbachia in a lab strain of the thelytokous Trichogramma cacoeciae was firstly identified based on amplification and sequencing part of the wsp gene. Aligned the resulting sequence with the published ones, the phylogenetic relationships among Wolbachia which was found in T. cacoeciae, T. dendrolimi and other insects were established. The Wolbachia that found in T. cacoeciae and in T. dendrolimi belong to the Kue group and the Pip group, respectively.展开更多
Intercropping maize with the prostrate variety of mungbean, Vigna radiata (L.) Wilczek which grows flat along the ground can increase parasitism of the eggs of the Asian corn borer, Ostrinia furnacalis (Guenée...Intercropping maize with the prostrate variety of mungbean, Vigna radiata (L.) Wilczek which grows flat along the ground can increase parasitism of the eggs of the Asian corn borer, Ostrinia furnacalis (Guenée), a crucial insect pest of maize in China, by Trichogramma ostriniae Pang Chen. This study investigated the behavioural responses of T. ostriniae to plant volatiles emitted from whole plants, leaves, and flowers of prostrate and erect varieties of mungbean in a 4-armed olfactometer. Female parasitiods were significantly attracted to the odours from some varieties of prostrate mungbean when the visit duration and the number of visits were considered, but were not attracted to the odours from any erect varieties. The attractive odours were shown to emanate from the leaves, rather than from the flowers of prostrate mungbean plants. These results have implications for the augmentation of Trichogramma parasitoids in bio-control of O. furnacalis and other crop pests.展开更多
The technology based on specific PCR amplification using internal transcribed spacer 2 of nuclear ribosomal DNA for molecular identification and detection of Trichogramma species was studied. Firstly the ITS2s of six ...The technology based on specific PCR amplification using internal transcribed spacer 2 of nuclear ribosomal DNA for molecular identification and detection of Trichogramma species was studied. Firstly the ITS2s of six Trichogramma species were cloned and sequenced, and the interspecific sequence variation was analyzed. Secondly the ITS2 regions of six geographical populations of T. dendrolimi were cloned and sequenced, and the intraspecific sequence identity was analyzed. The results show that the interspecific variation and intraspecific similarity of ITS2 sequences are very suitable for designation of specific primers at species-level. Screening of specific primers for T. dendrolimi leads to final sensitive and stable diagnostic primers. This system lets non-specialists can not only identify adults (males and females), but also identify eggs in parasitized hosts rapidly and accurately, which is impossible by conventional methods. Further development of this protocol can create a complete set of specific primers for different species of the whole genus Trichogramma .展开更多
The results of evaluation on field control efficacy of Trichogramma dendrolimi against Ostrinia furnacalis showed that the correction rates of Ostrinia furnacalis egg mass parasitism were 71.75% and 73.57%,the average...The results of evaluation on field control efficacy of Trichogramma dendrolimi against Ostrinia furnacalis showed that the correction rates of Ostrinia furnacalis egg mass parasitism were 71.75% and 73.57%,the average control effect were 65.85% and 70.24%,the restoration yield loss rates were 6.78% and 7.97%,input-output ratio at 1:27.8 and 1:33.5 in Longjiang county of Heilongjiang province in 2009 and 2010,respectively.The technology is a integration of advanced,practical,environmental safety,effective biocontrol measures,embodies the "public plant protection,green plant protection" fully,has significant economic,social and ecological benefits.展开更多
This study investigated the direct effect of the insecticides deltamethrin and spinosad on three egg parasitoids species: Trichogramma oleae, T. cacoeciae and T. bourarachae. The parasitoid pupae were exposed to pesti...This study investigated the direct effect of the insecticides deltamethrin and spinosad on three egg parasitoids species: Trichogramma oleae, T. cacoeciae and T. bourarachae. The parasitoid pupae were exposed to pesticide residues on fresh olive tree leaves at recommended concentrations (RC) at different time intervals: 3, 10, 17, 24 and 31 days after pesticide applications. Parasitism viability (% emergence from parasitized eggs) and adult emergence time (developmental time from pupa to adult emergence) were evaluated. Regarding to the International Organization of Biological Control (IOBC) guidelines, results of toxicity effects of insecticides show that: Deltamethrin was moderately harmful to all Trichogramma species at RC (Decis®100 milliliters·ha−1), however, spinosad was harmless to moderately harmful at RC (Tracer®20 milliliters·ha−1). Trichogramma species revealed differences with regard to adult emergence time and exhibited significant changes in parasitism viability with increasing time after pesticide treatment. While deltamethrin residues affected parasitism viability 31 days after the product application, spinosad displayed similar viability for almost species 24 days after the application. The usefulness of Trichogramma parasitoids used as biological control agents, in olive tree ecosystem, was discussed in integrated pest management programs for Prays oleae control when parasitoid species were exposed during pupal stage to the insecticide residue.展开更多
In this study, we investigated the efficiency of T. brassicae and T. embryophagum in combination with bacterial suspension of B. thuringiensis against the tomato leafminer T. absoluta eggs in cage inside greenhouse (s...In this study, we investigated the efficiency of T. brassicae and T. embryophagum in combination with bacterial suspension of B. thuringiensis against the tomato leafminer T. absoluta eggs in cage inside greenhouse (semi field) experiments. Four treatments were used (T. brassicae or T. embryophagum + T. absoluta) (T1), (B. thuringiensis + T. absoluta) (T2), (T. brassicae or T. embryophagum + B. thuringiensis + T. absoluta) (T3) and control (T4). The lowest number of T. absoluta mines (6.1, 0.5 mine per plant) were recorded in T3 for T. brassicae and T. embryophagum were significantly lower than those of all other treatments which were followed by T1 and T2, while the highest number of mines per plant (50.70) were recorded in control (T4). In addition, the parasitism rate, adults’ emergence, the number of females and adult longevity of two parasitoids were investigated. According to the obtained results, the highest parasitism rate was obtained for T. embryophagum when treated with Bt reared in the T. absoluta eggs (31.18%). However, no significant differences were detected between T. brassicae and T. embryophagum in mortality and adult emergence rates were found when they were treated with/ without Bt reared in the T. absoluta eggs in cage inside greenhouse. Also, the longevity of T. embryophagum was significantly better than T. brassicae p = 0.000. This is the first study to investigate T. embryophagum in cage inside greenhouse for parasitizing the eggs of T. absoluta and results of present study suggested that T. embryophagum with Bt could be more efficient for biocontrol of T. absoluta.展开更多
Assessment of quality of biological control agents is an important step for the success of any biocontrol program.Experiments were carried out to select candidate Trichogramma species for use in biological control of ...Assessment of quality of biological control agents is an important step for the success of any biocontrol program.Experiments were carried out to select candidate Trichogramma species for use in biological control of the olive moth Prays oleae Bern(Lepidoptera,Yponomeutidae).Thirteen local strains were preselected on the basis of the geographical origin and the availability from mass production of the rearing host Ephestia kuehniella ZELL.(Lepidoptera,Pyralidae) under laboratory conditions.Selection tests were focusing on acceptance and preference for P.oleae eggs.In the acceptance test,a single parasitoid female was offered P.oleae eggs on "tricho-card" for 6 hours at 25°C,70% HR and L16:D9 and assessed for parasitism after 6 days.The preference was determined by offering the choice and observing contacts with eggs of the target pest P.oleae and eggs of the host E.kuehniella.Parasitism was therefore assessed 6 days after the experiment under similar laboratory conditions.In host acceptance test,most eggs of P.oleae were parasited by strains belonging to the species T.oleae,T.bourarachae and T.cacoeciae.These strains also showed a high number of contacts with olive moth eggs in preference tests.However,a small number of T.bourarachae observed ovipositions resulted in successful parasitism.Therefore,T.oleae and T.cacoeciae were selected as candidates for further experiments.展开更多
Insect additives have been shown to improve the value of artificial media for Trichogramma species, but at the same time maintain dependence on parallel cultures of host insects. In the present study, Trichogramma den...Insect additives have been shown to improve the value of artificial media for Trichogramma species, but at the same time maintain dependence on parallel cultures of host insects. In the present study, Trichogramma dendrolimi Matsumura was reared in vitro from egg to adult on artificial media with different contents of pupal hemolymph of Chinese oak silkmoth Antheraea pernyi (Guérin-Méneville) and with supplements of distilled water, or of trehalose dissolved in water or in Grace's insect medium. The results indicated insect hemolymph was the key component of artificial medium. Developmental parameters, including rates of parasitism, pupation, adult emergence and normal adults, and numbers of produced adults, were increased on media supplemented with trehalose even when the proportion of pupal hemolymph was reduced. Two artificial media, the first containing 30% hemolymph and 10% trehalose in water with 98.9% parasitism rate, 77.7.0% pupation rate, 77.2% emergence rate, 80.0% normal adult rate and 333 produced adults, and the second containing 25% hemolymph and 15% trehalose in Grace's insect medium with 97.8% parasitism rate, 91.0% pupation rate, 85.2% emergence rate, 76.1% normal adult rate and 757 produced adults, were believed to hold potential to mass produce T. dendrolimi. The use of trehalose to partially replace pupal hemolymph in artificial medium of this and other Trichogramma species may contribute to a significant reduction in their production cost and may as such help to evade problems related to short supplies of lepidopteran eggs, which currently constitute the main factitious host for the mass rearing of the parasitoids.展开更多
为明确30%乙螨唑悬浮剂、23%阿维菌素·乙螨唑悬浮剂和15%乙螨唑·唑螨酯悬浮剂等3种杀螨剂对松毛虫赤眼蜂和七星瓢虫的急性毒性效应和初级风险,采用试管药膜法分别测定了3种杀螨剂对松毛虫赤眼蜂和七星瓢虫的急性毒性,并预测...为明确30%乙螨唑悬浮剂、23%阿维菌素·乙螨唑悬浮剂和15%乙螨唑·唑螨酯悬浮剂等3种杀螨剂对松毛虫赤眼蜂和七星瓢虫的急性毒性效应和初级风险,采用试管药膜法分别测定了3种杀螨剂对松毛虫赤眼蜂和七星瓢虫的急性毒性,并预测杀螨剂在农田内外的暴露量,表征毒性风险。结果表明:3种杀螨剂对松毛虫赤眼蜂急性接触毒性LR50为0.255~63.400 g a.i./hm^(2);对七星瓢虫的急性接触毒性LR_(50-48 h)和LR_(50-16 d)分别为9.30~21.70 g a.i./hm^(2)和3.72~8.36 g a.i./hm^(2)。30%乙螨唑悬浮剂和15%乙螨唑·唑螨酯悬浮剂在农田内外对松毛虫寄生蜂的危害商值HQ均小于5,风险可接受;23%阿维菌素·乙螨唑悬浮剂在农田内外对松毛虫寄生蜂的危害商值HQ均大于5,风险不可接受;30%乙螨唑悬浮剂和23%阿维菌素·乙螨唑悬浮剂对七星瓢虫的农田内危害商值HQ均大于5,风险不可接受;15%乙螨唑·唑螨酯悬浮剂对七星瓢虫的农田内危害商值HQ均小于5,风险可接受;3种杀螨剂对七星瓢虫的农田外危害商值HQ均小于5,风险可接受。综之,2种复配杀螨剂相比单剂的毒性增大,30%乙螨唑悬浮剂和23%阿维菌素·乙螨唑悬浮剂对非靶标节肢动物的风险均不可接受,农药施用时需采用一些风险降低措施来减轻对松毛虫赤眼蜂和七星瓢虫的风险。展开更多
Trichogramma brassicae(Bezdenko)is an important biological control agent that has been used widely against many lepidopteran pests.Commonly,colonies of Trichogramma are mass reared on factitious hosts such as Sitotrog...Trichogramma brassicae(Bezdenko)is an important biological control agent that has been used widely against many lepidopteran pests.Commonly,colonies of Trichogramma are mass reared on factitious hosts such as Sitotroga cerealella(Olivier)over many generations.In this study,we evaluated the quality and performance of a colony of T.brassicae that had been reared for over 45 generations(G)using two-sex life table parameters and parasitism capacity.We found that female adult longevity was significantly different among sequential generations,ranging from 5.58±2.5 d(at G5)to 3.75±1.42 d(at G45).However,no significant difference was found in male adult longevity among different generations.Although female wasps survived longer until the 15th gener・ation,they allocated more days for egg laying at G5 and GIO.The highest values of gross reproductive rate(GRR),net reproductive rate(7.),intrinsic rate of increase(r),finite rate of increase(λ)and mean generation time(T)were found in G5 and GIO,which also showed significantly higher cq.No significant difference in the finite parasitism rate(co)was found among generations up to G15.These results suggest that T.brassicae wasps held under continuous laboratory rearing can be used successfully in biological control programs until the 15th generation without any loss of quality or performance.However,laboratory mass rearing colonies declined in quality after 15 generations and we suggest that they should be rejuvenated regularly by adding field-collected parasitoids periodically.展开更多
Cadra(Ephestia)cautella(Walker)is a moth that attacks dates from ripening stages while on tree,throughout storage,and until consumption,causing enormous qualitative and quantitative damages,resulting in economic losse...Cadra(Ephestia)cautella(Walker)is a moth that attacks dates from ripening stages while on tree,throughout storage,and until consumption,causing enormous qualitative and quantitative damages,resulting in economic losses.Image-processing algorithms were developed for detecting and differentiating between three Cadra egg categories based on the success of Trichogramma bourarachae(Pintureau and Babaul)parasitization.These categories were parasitized(black and dark red),unparasitized fertile unhatched(yellow),and unparasitized hatched(white)eggs.Color,light intensity,and shape information was used to develop detection algorithms.Two image processing methods were developed based on three randomly selected images and were tested on a larger validation image set of 40 images:(i)segmentation and extractions of color and morphological features followed by Watershed delineation,and is referred to as Algorithm 1(ALGO1),(ii)finding circular objects by Hough Transformation followed by convolution filtering,and is referred to as Algorithm 2(ALGO2).ALGO1 and ALGO2 achieved correct classification rates(CCRs)for parasitized eggs of 92%and 96%,respectively.Their CCRs for unhatched eggs were 48%and 94%,and for hatched eggs were 42%and 73%,respectively.Regarding parasitized eggs,both methods performed satisfactorily,but,in general,ALGO2 outperformed ALGO1.These results ensure automatic evaluation of the efficiency of biological control of Cadra cautella by the egg parasitoid Trichogramma bourarachae by quantifying the rate of parasitization.The developed detection methods can be used by producers of biocontrol agents for online monitoring of Trichogramma and similar insect natural enemies during mass production and before release against crop pests.Moreover,with few adjustments these methods can be used in similar applications such as detecting plant diseases.展开更多
文摘Wolbachia is a symbiotic bacterium that alters reproductive behavior of numerous arthropods. It is the most advanced way to study phytogeny and classification based on sequences of the wsp gene. The presence of Wolbachia in a lab strain of the thelytokous Trichogramma cacoeciae was firstly identified based on amplification and sequencing part of the wsp gene. Aligned the resulting sequence with the published ones, the phylogenetic relationships among Wolbachia which was found in T. cacoeciae, T. dendrolimi and other insects were established. The Wolbachia that found in T. cacoeciae and in T. dendrolimi belong to the Kue group and the Pip group, respectively.
基金supported by the National Natural Sci-ence Foundation of China (39770513)the Coop-erative Research Project between the National Crop Ex-periment Station, Rural Development Administration,Republic of Korea and the Institute of Plant Protection,Chinese Academy of Agricultural Sciences, China
文摘Intercropping maize with the prostrate variety of mungbean, Vigna radiata (L.) Wilczek which grows flat along the ground can increase parasitism of the eggs of the Asian corn borer, Ostrinia furnacalis (Guenée), a crucial insect pest of maize in China, by Trichogramma ostriniae Pang Chen. This study investigated the behavioural responses of T. ostriniae to plant volatiles emitted from whole plants, leaves, and flowers of prostrate and erect varieties of mungbean in a 4-armed olfactometer. Female parasitiods were significantly attracted to the odours from some varieties of prostrate mungbean when the visit duration and the number of visits were considered, but were not attracted to the odours from any erect varieties. The attractive odours were shown to emanate from the leaves, rather than from the flowers of prostrate mungbean plants. These results have implications for the augmentation of Trichogramma parasitoids in bio-control of O. furnacalis and other crop pests.
文摘The technology based on specific PCR amplification using internal transcribed spacer 2 of nuclear ribosomal DNA for molecular identification and detection of Trichogramma species was studied. Firstly the ITS2s of six Trichogramma species were cloned and sequenced, and the interspecific sequence variation was analyzed. Secondly the ITS2 regions of six geographical populations of T. dendrolimi were cloned and sequenced, and the intraspecific sequence identity was analyzed. The results show that the interspecific variation and intraspecific similarity of ITS2 sequences are very suitable for designation of specific primers at species-level. Screening of specific primers for T. dendrolimi leads to final sensitive and stable diagnostic primers. This system lets non-specialists can not only identify adults (males and females), but also identify eggs in parasitized hosts rapidly and accurately, which is impossible by conventional methods. Further development of this protocol can create a complete set of specific primers for different species of the whole genus Trichogramma .
基金The National public service sectors (agriculture) research special (201103002)
文摘The results of evaluation on field control efficacy of Trichogramma dendrolimi against Ostrinia furnacalis showed that the correction rates of Ostrinia furnacalis egg mass parasitism were 71.75% and 73.57%,the average control effect were 65.85% and 70.24%,the restoration yield loss rates were 6.78% and 7.97%,input-output ratio at 1:27.8 and 1:33.5 in Longjiang county of Heilongjiang province in 2009 and 2010,respectively.The technology is a integration of advanced,practical,environmental safety,effective biocontrol measures,embodies the "public plant protection,green plant protection" fully,has significant economic,social and ecological benefits.
文摘This study investigated the direct effect of the insecticides deltamethrin and spinosad on three egg parasitoids species: Trichogramma oleae, T. cacoeciae and T. bourarachae. The parasitoid pupae were exposed to pesticide residues on fresh olive tree leaves at recommended concentrations (RC) at different time intervals: 3, 10, 17, 24 and 31 days after pesticide applications. Parasitism viability (% emergence from parasitized eggs) and adult emergence time (developmental time from pupa to adult emergence) were evaluated. Regarding to the International Organization of Biological Control (IOBC) guidelines, results of toxicity effects of insecticides show that: Deltamethrin was moderately harmful to all Trichogramma species at RC (Decis®100 milliliters·ha−1), however, spinosad was harmless to moderately harmful at RC (Tracer®20 milliliters·ha−1). Trichogramma species revealed differences with regard to adult emergence time and exhibited significant changes in parasitism viability with increasing time after pesticide treatment. While deltamethrin residues affected parasitism viability 31 days after the product application, spinosad displayed similar viability for almost species 24 days after the application. The usefulness of Trichogramma parasitoids used as biological control agents, in olive tree ecosystem, was discussed in integrated pest management programs for Prays oleae control when parasitoid species were exposed during pupal stage to the insecticide residue.
文摘In this study, we investigated the efficiency of T. brassicae and T. embryophagum in combination with bacterial suspension of B. thuringiensis against the tomato leafminer T. absoluta eggs in cage inside greenhouse (semi field) experiments. Four treatments were used (T. brassicae or T. embryophagum + T. absoluta) (T1), (B. thuringiensis + T. absoluta) (T2), (T. brassicae or T. embryophagum + B. thuringiensis + T. absoluta) (T3) and control (T4). The lowest number of T. absoluta mines (6.1, 0.5 mine per plant) were recorded in T3 for T. brassicae and T. embryophagum were significantly lower than those of all other treatments which were followed by T1 and T2, while the highest number of mines per plant (50.70) were recorded in control (T4). In addition, the parasitism rate, adults’ emergence, the number of females and adult longevity of two parasitoids were investigated. According to the obtained results, the highest parasitism rate was obtained for T. embryophagum when treated with Bt reared in the T. absoluta eggs (31.18%). However, no significant differences were detected between T. brassicae and T. embryophagum in mortality and adult emergence rates were found when they were treated with/ without Bt reared in the T. absoluta eggs in cage inside greenhouse. Also, the longevity of T. embryophagum was significantly better than T. brassicae p = 0.000. This is the first study to investigate T. embryophagum in cage inside greenhouse for parasitizing the eggs of T. absoluta and results of present study suggested that T. embryophagum with Bt could be more efficient for biocontrol of T. absoluta.
基金INCODEV (TRIPHELIO) (UE/ 2002-2005) :Sustainable Control of Lepidopterous Pests in Olive Groves - Integration of Egg Parasitoids and Pheromones
文摘Assessment of quality of biological control agents is an important step for the success of any biocontrol program.Experiments were carried out to select candidate Trichogramma species for use in biological control of the olive moth Prays oleae Bern(Lepidoptera,Yponomeutidae).Thirteen local strains were preselected on the basis of the geographical origin and the availability from mass production of the rearing host Ephestia kuehniella ZELL.(Lepidoptera,Pyralidae) under laboratory conditions.Selection tests were focusing on acceptance and preference for P.oleae eggs.In the acceptance test,a single parasitoid female was offered P.oleae eggs on "tricho-card" for 6 hours at 25°C,70% HR and L16:D9 and assessed for parasitism after 6 days.The preference was determined by offering the choice and observing contacts with eggs of the target pest P.oleae and eggs of the host E.kuehniella.Parasitism was therefore assessed 6 days after the experiment under similar laboratory conditions.In host acceptance test,most eggs of P.oleae were parasited by strains belonging to the species T.oleae,T.bourarachae and T.cacoeciae.These strains also showed a high number of contacts with olive moth eggs in preference tests.However,a small number of T.bourarachae observed ovipositions resulted in successful parasitism.Therefore,T.oleae and T.cacoeciae were selected as candidates for further experiments.
基金This study was supported by the National Natural Science Foundation of China Program "Optimization of Artificial Diets Composition for Rearing Trichogramma and Reproduction Quality Control (Grant No.31171903)".
文摘Insect additives have been shown to improve the value of artificial media for Trichogramma species, but at the same time maintain dependence on parallel cultures of host insects. In the present study, Trichogramma dendrolimi Matsumura was reared in vitro from egg to adult on artificial media with different contents of pupal hemolymph of Chinese oak silkmoth Antheraea pernyi (Guérin-Méneville) and with supplements of distilled water, or of trehalose dissolved in water or in Grace's insect medium. The results indicated insect hemolymph was the key component of artificial medium. Developmental parameters, including rates of parasitism, pupation, adult emergence and normal adults, and numbers of produced adults, were increased on media supplemented with trehalose even when the proportion of pupal hemolymph was reduced. Two artificial media, the first containing 30% hemolymph and 10% trehalose in water with 98.9% parasitism rate, 77.7.0% pupation rate, 77.2% emergence rate, 80.0% normal adult rate and 333 produced adults, and the second containing 25% hemolymph and 15% trehalose in Grace's insect medium with 97.8% parasitism rate, 91.0% pupation rate, 85.2% emergence rate, 76.1% normal adult rate and 757 produced adults, were believed to hold potential to mass produce T. dendrolimi. The use of trehalose to partially replace pupal hemolymph in artificial medium of this and other Trichogramma species may contribute to a significant reduction in their production cost and may as such help to evade problems related to short supplies of lepidopteran eggs, which currently constitute the main factitious host for the mass rearing of the parasitoids.
文摘为明确30%乙螨唑悬浮剂、23%阿维菌素·乙螨唑悬浮剂和15%乙螨唑·唑螨酯悬浮剂等3种杀螨剂对松毛虫赤眼蜂和七星瓢虫的急性毒性效应和初级风险,采用试管药膜法分别测定了3种杀螨剂对松毛虫赤眼蜂和七星瓢虫的急性毒性,并预测杀螨剂在农田内外的暴露量,表征毒性风险。结果表明:3种杀螨剂对松毛虫赤眼蜂急性接触毒性LR50为0.255~63.400 g a.i./hm^(2);对七星瓢虫的急性接触毒性LR_(50-48 h)和LR_(50-16 d)分别为9.30~21.70 g a.i./hm^(2)和3.72~8.36 g a.i./hm^(2)。30%乙螨唑悬浮剂和15%乙螨唑·唑螨酯悬浮剂在农田内外对松毛虫寄生蜂的危害商值HQ均小于5,风险可接受;23%阿维菌素·乙螨唑悬浮剂在农田内外对松毛虫寄生蜂的危害商值HQ均大于5,风险不可接受;30%乙螨唑悬浮剂和23%阿维菌素·乙螨唑悬浮剂对七星瓢虫的农田内危害商值HQ均大于5,风险不可接受;15%乙螨唑·唑螨酯悬浮剂对七星瓢虫的农田内危害商值HQ均小于5,风险可接受;3种杀螨剂对七星瓢虫的农田外危害商值HQ均小于5,风险可接受。综之,2种复配杀螨剂相比单剂的毒性增大,30%乙螨唑悬浮剂和23%阿维菌素·乙螨唑悬浮剂对非靶标节肢动物的风险均不可接受,农药施用时需采用一些风险降低措施来减轻对松毛虫赤眼蜂和七星瓢虫的风险。
文摘Trichogramma brassicae(Bezdenko)is an important biological control agent that has been used widely against many lepidopteran pests.Commonly,colonies of Trichogramma are mass reared on factitious hosts such as Sitotroga cerealella(Olivier)over many generations.In this study,we evaluated the quality and performance of a colony of T.brassicae that had been reared for over 45 generations(G)using two-sex life table parameters and parasitism capacity.We found that female adult longevity was significantly different among sequential generations,ranging from 5.58±2.5 d(at G5)to 3.75±1.42 d(at G45).However,no significant difference was found in male adult longevity among different generations.Although female wasps survived longer until the 15th gener・ation,they allocated more days for egg laying at G5 and GIO.The highest values of gross reproductive rate(GRR),net reproductive rate(7.),intrinsic rate of increase(r),finite rate of increase(λ)and mean generation time(T)were found in G5 and GIO,which also showed significantly higher cq.No significant difference in the finite parasitism rate(co)was found among generations up to G15.These results suggest that T.brassicae wasps held under continuous laboratory rearing can be used successfully in biological control programs until the 15th generation without any loss of quality or performance.However,laboratory mass rearing colonies declined in quality after 15 generations and we suggest that they should be rejuvenated regularly by adding field-collected parasitoids periodically.
文摘Cadra(Ephestia)cautella(Walker)is a moth that attacks dates from ripening stages while on tree,throughout storage,and until consumption,causing enormous qualitative and quantitative damages,resulting in economic losses.Image-processing algorithms were developed for detecting and differentiating between three Cadra egg categories based on the success of Trichogramma bourarachae(Pintureau and Babaul)parasitization.These categories were parasitized(black and dark red),unparasitized fertile unhatched(yellow),and unparasitized hatched(white)eggs.Color,light intensity,and shape information was used to develop detection algorithms.Two image processing methods were developed based on three randomly selected images and were tested on a larger validation image set of 40 images:(i)segmentation and extractions of color and morphological features followed by Watershed delineation,and is referred to as Algorithm 1(ALGO1),(ii)finding circular objects by Hough Transformation followed by convolution filtering,and is referred to as Algorithm 2(ALGO2).ALGO1 and ALGO2 achieved correct classification rates(CCRs)for parasitized eggs of 92%and 96%,respectively.Their CCRs for unhatched eggs were 48%and 94%,and for hatched eggs were 42%and 73%,respectively.Regarding parasitized eggs,both methods performed satisfactorily,but,in general,ALGO2 outperformed ALGO1.These results ensure automatic evaluation of the efficiency of biological control of Cadra cautella by the egg parasitoid Trichogramma bourarachae by quantifying the rate of parasitization.The developed detection methods can be used by producers of biocontrol agents for online monitoring of Trichogramma and similar insect natural enemies during mass production and before release against crop pests.Moreover,with few adjustments these methods can be used in similar applications such as detecting plant diseases.