Traditional Insecticides Research Articles

Pesticide-Induced Planthopper Population Resurgence in Rice Cropping Systems.

Planthoppers are serious rice pests in Asia. Their population resurgence was first reported in the early 1960s, caused mainly by insecticides that indiscriminately killed beneficial arthropods and target pests. The subsequent resurgence involved two mechanisms, the loss of beneficial insects and insecticide-enhanced planthopper reproduction. In this review, we identify two forms of resurgence, acute and chronic. Acute resurgence is caused by traditional insecticides with rapid resurgence in the F1 generation. Chronic resurgence follows application of modern pesticides, including fungicides and herbicides, with low natural enemy toxicity, coupled with stimulated planthopper reproduction. The chemical-driven syndrome of changes leads to later resurgence in the F2 or later generations. Chronic resurgence poses new threats to global rice production. We review findings on the physiological and molecular mechanisms of chronic planthopper resurgence and suggest research directions that may help manage these new threats.

Sublethal effects of methylthio-diafenthiuron on the life table parameters and enzymatic properties of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)

The diamondback moth (DBM), Plutella xylostella (L.), is a major pest affecting cruciferous vegetables, and seriously affects the quality and yield of these vegetables. Diafenthiuron is a traditional thiourea-based insecticide, but it is rarely used to control pests on cruciferous vegetables due to its phytotoxicity on these vegetables under high temperature and light conditions. Thus, there is an ongoing need for more effective pesticides that can be used on cruciferous vegetables, possibly including new formulations of diafenthiuron. A new thiourea insecticide, methylthio-diafenthiuron, is intended to optimize the structure of diafenthiuron not only to preserve its insecticidal bioactivity but also to overcome its phytotoxicity to cruciferous vegetables, aiming to control insect pests on cruciferous vegetables. In this study, we compared the toxicity of methylthio-diafenthiuron to some frequently used insecticides on the third-instar larvae of DBM. The parental pupal duration was significantly longer under the treatment than in the control, but the pupal weight, fecundity, and hatching rate significantly decreased. By studying the changes in three detoxifying enzymes within 72 h after treatment with a sublethal concentration, the activity of CarE and ODM in the treatment group significantly increased at first and then decreased. In addition, methylthio-diafenthiuron clearly inhibited three kinds of ATPases in the DBM and significantly reduced the eclosion rate of the pupae. This research provides valuable information for the assessment and rational application of methylthio-diafenthiuron for the control of pests on cruciferous vegetables.

Evaluation of the Persistence of Three Larvicides Used To Control Aedes aegypti In Arapiraca, Northeastern Brazil.

The chemical control of the mosquito Aedes aegypti is a great challenge worldwide, since several populations of this species are already resistant to traditional insecticides, such as temephos. In Brazil, alternative larvicides, such as Bacillus thuringiensis israelensis (Bti) and pyriproxyfen, have been used more recently. In this study we evaluated the persistence of pyriproxyfen (Sumilarv 0.5%G), 2 commercial formulations of Bti (Vectobac WDG and Vectobac G), and temephos (Fersol 1G) under field and simulated field conditions with treatments exposed to sun and shadow. In the field tests, the 2 formulations of Bti presented less persistence in the 8th wk of evaluation (46% and 37% positivity) compared with temephos (3.6% and 6.8% positivity) and Sumilarv (6.6% and 3.8% positivity) in containers exposed to the sun and shadow, respectively. In the simulated field trial, temephos and the 2 formulations of Bti presented high persistence (100% mortality at 8th wk) when applied in the water box and in deposits placed in the shade. In containers exposed to the sun, the persistence of these products was lower (>80% mortality by temephos after 4 wk, Bti formulations for 3 wk, and Sumilarv for 6 wk). Based on these data, however, Sumilarv presented better performance in the containers exposed to the sun than the 2 formulations of Bti (Vectobac G and Vectobac WDG), which were affected by the sun.

Comparison between two insecticide application methods in controlling lesser mealworm beetles in commercial broiler housessser mealworm beetles in commercial broiler houses

The lesser mealworm control is mostly made by insecticides, as the association of chlorpyrifos, cypermethrin and citronellal. The traditional insecticide application method (TRADM) depends on many liters of water and, with the objective of reducing water consumption, the aim was to compare TRADM with atomizer-equipment method (ATOMM). Four and three houses from farm A and B were used, respectively. Houses 1, 3 and 7 were treated with TRADM (1 liter of insecticide diluted in 500 liters of water) and houses 2, 4, 5 and 6 with ATOMM (1 liter of insecticide diluted in 9 liters of water). Twenty-four hours before and 30 (for farm A) and 45 days (for farm B) after the insecticide application, the number of insects was counted in each house (using 18 mapped traps/house). Farms were not considered different (p>0.05) and comparison was made between the houses. Houses were different (p<0.001) in the pre-treatment count, but they were equal in the second count (p=0.97). The insecticide application increased the number of traps without any insect (p<0.0001). In conclusion, the application method of chlorpyrifos, cypermethrin, and citronellal insecticide using atomizer equipment presented similar results than using the traditional application method. Both methods were effective in reducing the infestation of all houses, not making any difference if the dilution of the product was in 500 liters or in 9 liters of water; thus, it is possible to spend less water to run this management.

TOXICOLOGICAL AND BIOCHEMICAL EFFECTS OF PRECOCENE II AGAINST COTTON LEAFWORM, SPODOPTERA LITTORALIS (BOISD.)

The cotton leafworm, Spodoptera littoralis (Boisd.) is very polyphagous insect against the most economic plants all over the world. The traditional synthetic chemical insecticides had dramatic effect on the living organisms including man. Anti-juvenile hormones; precocene II effect on the cotton leafworm, Spodoptera littoralis were assayed under laboratory conditions. (PrecoceneII (6,7-dimethoxy-2,2dimethylchromene) was the main constituent isolated from Ageratum houstonianum plant. The compound caused toxicity against the larvae with (LC10 was 5.59 mg/l), (LC25 was 24.69 mg/l) and (LC50 was 128.53 mg/l). There was some morphogenic effect obtained due to effect of precoceneII on larvae, pupae and adult stages. On the other hands the biochemical analysis of the cotton leafworm revealed that precocene II caused significant increase in chitinase, protease and total carbohydrates with (17.32, 50.17 and 36.85 %), respectively comparison to control.

Consequences of use of fenpropathrin compared to other fish toxicants in commercial aquaculture

Use of fish toxicants is an important management tool in inland commercial aquaculture. In entrepreneurial fishery in northwest Bangladesh where pond ownership (using rights due to lease) changes frequently (every few years) use of fish toxicants is very routine and more crucial. Along with some traditional fish toxicants (rotenone and aluminium phosphide), unconventional and insecticides like fenpropathrin (not approved for aquaculture use) are being used by fish farm owners in northwest Bangladesh. The study was conducted to understand the consequences of use of fenpropathrin compared to other traditional fish toxicants in commercial aquaculture for harvesting of food fish. Of all the toxicants, fenpropathrin’ s impact was lowest on zooplankton and aquatic insect population, while rotenone had the lowest impact on benthos population in terms of killing and quick recovery time for the population, primarily due to the high turbidity (suspended soil particle) of the pond water (under this study) by which both fenpropathrin and rotenone got affected. Aluminium phosphide found to be more damaging in terms of killing and relatively longer recovery time for zooplankton, aquatic insect and benthos population. Using convenience, quick killing, cheaper price, short duration of toxicity and no potential long-term damage of the waterbody contributes positively for fenpropathrin as fish toxicant except the severe potential public health concern from eating of fish killed by fenpropathrin due to very high bioconcentration factor of fenpropathrin; hence, demands regulation of fenpropathrin’ s use as fish toxicants for food fish.
 Asian Australas. J. Food Saf. Secur. 2019, 3(1), 27-37

Selectivity of novel and traditional insecticides used for management of whiteflies on the parasitoid Encarsia formosa.

Encarsia formosa Gahan is the most important parasitoid exploited for the control of whitefly pests of vegetable crops. However, the non-target effects of recently developed insecticides for controlling whiteflies toward this biocontrol agent is little documented. Here we evaluated the susceptibility of E. formosa adults and juveniles to eight commonly used insecticides against whiteflies. Residual toxicity tests on glass showed that E. formosa adults were susceptible (over 98% mortality after 6h treated) to field concentrations of the tested neonicotinoids (imidacloprid, acetamiprid, nitenpyram and thiamethoxam), abamectin, cyantraniliprole, and sulfoxaflor at their field concentrations. Pyriproxyfen was harmless to both adult and pupae of E. formosa. A risk quotient analysis showed that toxicity of pyriproxyfen to E. formosa adults was the lowest, followed by acetamiprid and cyantraniliprole. In the leaf residues test, mortality of E. formosa adults under all insecticides decreased when the residue age increased. Interestingly, E. formosa experiencing contact with the residues of most insecticides, except pyriproxyfen and abamectin, parasitized significantly more hosts 5-days after treatment, suggesting a hormetic effect on parasitism. The risk assessment of insecticides indicated that pyriproxyfen and cyantraniliprole were the least toxic to E. formosa. Our results suggest that the inclusion of the insecticides in sustainable integrated pest management programs of whiteflies should be carefully evaluated on a case-by-case basis. © 2019 Society of Chemical Industry.

Effects of bistrifluron resistance on the biological traits of Spodoptera litura (Fab.) (Noctuidae: Lepidoptera).

Spodoptera litura is one of the major insect pests of vegetables in Sichuan, China, and it has developed serious resistance to many traditional chemical insecticides. In this present study, S. litura individuals collected from five regions in Sichuan in 2017, which were detected the resistance to bistrifluron. We found that the resistance ratios (RRs) bistrifluron were in the ranges of 15.9- to 77.7-fold, respectively, compared with a laboratory susceptible (Lab-HN) strain. To elucidate the effect of bistrifluron on the life history parameters of S. litura, we established the bistrifluron-susceptible (Bis-UNSEL) and bistrifluron-resistant (Bis-SEL) strains based on the DY field population with the highest RR of 77.7-fold among the all field populations to bistrifluron compared with a laboratory Lab-HN strain. The results show that the Bis-SEL strain developed a 113.8-fold RR while that of the Bis-UNSEL strain was almost equal to that of the Lab-HN strain (with overlapping confidence intervals (CI) of their LC50 values, P < 0.05). Meanwhile, the life span of the egg and pupa stage of the Bis-UNSEL strain was prolonged, and the strain also showed shorter adult duration and lower fecundity. Demographic characteristics, such as the intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) in the Bis-SEL strain were significantly higher than the Bis-UNSEL strain, whereas the mean generation time (T) and gross reproduction rate (GRR) were lower. The results clearly showed that the developing resistance of bistriflueon on S. litura promoted its population growth. Therefore, the present study could provide useful informations for determining potential management methods to prevent the development of bistrifluron resistance in S. litura.

4-Aryl-5-carbamoyl-3-isoxazolols as competitive antagonists of insect GABA receptors: Synthesis, biological activity, and molecular docking studies.

Competitive antagonists (CAs) of ionotropic GABA receptors (GABARs) reportedly exhibit insecticidal activity and have potential for development as novel insecticides for overcoming emerging resistance to traditional GABAR-targeting insecticides. Our previous studies demonstrated that 4,5-disubstituted 3-isoxazolols or 3-isothiazolols are an important class of insect GABAR CAs. In the present study, we synthesized a series of 4-aryl-5-carbamoyl-3-isoxazolols and examined their antagonism of insect GABARs expressed in Xenopus oocytes. Several of these 3-isoxazolols exhibited potent antagonistic activities against housefly and common cutworm GABARs, with IC50 values in the low-micromolar range in both receptors. 4-(3-Amino-4-methylphenyl)-5-carbamoyl-3-isoxazolol (3u) displayed the highest antagonism, with IC50 values of 2.0 and 0.9 μM in housefly and common cutworm GABARs, respectively. Most of the synthesized 3-isoxazolols showed moderate larvicidal activities against common cutworms, with more than 50% mortality at 100 μg/g. These results indicate that 4-monocyclic aryl-5-carbamoyl-3-isoxazolol is a promising scaffold for insect GABAR CA discovery and provide important information for the design and development of GABAR-targeting insecticides with a novel mode of action.

Efficacy of Beauveria bassiana in combination with an electrostatically charged dust for the control of major stored-product beetle species on concrete

Laboratory bioassays were carried out to determine the insecticidal efficacy of a Beauveria bassiana formulation (Bb38, Exosect Ltd, UK), which is based on the combined use of the fungus with the electrostatically charged dust Entostat. The efficacy of Bb38 was conducted on concrete surfaces against adults of the lesser grain borer, Rhyzopertha dominica, the rice weevil, Sitophilus oryzae, the confused flour beetle, Tribolium confusum and the rusty grain beetle, Cryptolestes ferrugineus, in two series of bioassays. In the first series, adults of the above species were exposed on concrete surfaces treated with Bb38 and mortality was recorded after 7 and 14 days of exposure (immediate mortality). These tests were carried out in all combinations of two temperatures, i.e. 25 and 30° C and two levels of relative humidity (r.h.), i.e. 55 and 75%. In the second series of bioassays, adults of the above species were exposed to Bb38 for 7 days, and after this interval, the surviving individuals were transferred in untreated concrete, where mortality was recorded again 7 and 14 days later (delayed mortality). From the species tested, R. dominica was by far the most susceptible, given that mortality reached 100% in almost all temperatures and r.h. levels. From the other species, S. oryzae and C. ferrugineus were moderately susceptible, while Bb38 was less effective for T. confusum. In the second series, immediate mortality for R. dominica was much higher than that of the other species. Moreover, delayed mortality of R. dominica reached 100% in contrast with the other species, where delayed mortality was low. Based on the results of the present work, we found that the insecticidal effect of Bb38 is not affected much by temperature and r.h., for the vast majority of the species and conditions tested. Moreover, in some cases, there was some post-exposure delayed activity of the formulation. This is one of the few studies that examine commercial formulations of fungal-based insecticides against stored product insects, which are expected to provide solutions in stored product protection, where traditional insecticides cannot be applied, as in the case of organic products.

AN ECONOMIC IMPACT OF INTEGRATED CONTROL PROGRAM OF COTTON CROPS IN GHARBIA GOVERNORATE

The Agricultural production in Egypt is considered one of the most important productive sectors in national production, where most of its products of importance for food security in Egypt, the value of pesticides used in Egyptian agriculture is about 347.2, 287.2, 346.4 million pounds at a rate estimated at 35.4%, 29.3%, 35.3% for each of the pesticides and indigenous and grass on respectively of the total value of agricultural pesticides amounting to 980.8 million pounds in 201.6 The problem of the study focuses on the evaluation of economic and environmental impact on integrated pest management which afflict the cotton crops in Gharbia Governorate. The study aims to measure the economic and environmental impact of the use of integrated pest control of the production of cotton crops in Gharbia Governorate. The study showed that the most important factors affecting the production of the cotton crop in the first category, with the study sample in Gharbia governorate 2016 are: the amount of human labor, the quantity of seeds, the value of biological resistance the total productive elasticity amounted to about 0.867 that means the declining productive relationship, and the value of the marginal product of those elements of about 87.0, 249.3, 873.5 pound / kantar respectively, while the unit price of the element reached about 42.19, 5.39, 50.0 pound/unit respectively. In the second category and it was discovered that the most important factors affecting the cotton production are: the mechanical caber (irrigation) , the quantity of seeds, chemical resistance Value and the productive elasticity total amounted to about 0.923, while the value of marginal product of those elements toward 317.4, 423.2, 270.65 pound/ kantar respectively, while the unit price of the element toward 24.53, 5.43, 100.07 pounds / respectively, which refers to the efficiency of those elements in the equation of cotton production in the second category of study. The Study showed that: the nominal protection coefficient of production requirement, outputs, biological resistance, and effective protection coefficient of the cotton crop in the study sample year 2016 reached about 0.88, 0.75, 0.83, 0.88, whereas the domestic relative competitive coefficient (DRC) reached about 0.62, this means there is relative competitive in cotton production in Egypt. The results of productive policy martin analysis for cotton crop year 2016, there is a negative impacts on the total feddan return, and added value. The study explained that the environmental impact of important pesticides used by farmers of cotton and potato crop in sampling study of traditional insecticides in Gharbia governorate, came in the first rank sbedoo and mankozub pesticide with the quantity of 0.29, 0.58 kg/ feddan with safety period of 20, 7 days respectively. As the pesticides developed comes in the first rank : marshal and police .m.f with the quantity of 0.84, 0.5 kg /feddan with safety period 7 , 3 days respectively, the two pesticides non-pollution to the environment, we conclude that the pesticides developed less harm to the environment than traditional insecticides. The recommendations 1- It is necessary to educate the farmers with pesticide damage to human, animal and plant health and the environment. 2- The expansion in the use of the biological resistance in order to increase the quality of cotton, on one hand, and reducing the cost of chemical resistance on the other hand, for keeping the general health. 3- It should be setting a program for training cotton farmers on optimum using for pesticides in the allowable limits worldwide for keeping the health of the human, plant and the environment. 4- The imposition of a tax on users of highly toxic pesticides, which contributes to the transformation of the farmers to use clean agriculture, or setting a low to crime the using no useful. 5- It should stimulate cotton farmers using pesticide at least scale and following the method of integrated control. 6- It is necessary to devise new cotton strains of high productivity and resistance to pests and supply the farmers with it and saved it for farmers to encourage them to increase the captivated area of cotton in Egypt.

HISTOLOGICL EFFECTS OF TWO CHITIN SYNTHESIS INHIBITORS ON THE LARVAL MIDGUT OF THE COTTON LEAFWORM, SPODOPTERA LITTORALIS (BOISD.)(LEPIDOPTERA:NOCTUIDAE)

the histological effects of two chitin synthesis inhibitors (CISs) on the larvae of the cotton leafworm were investigated under the laboratory conditions. Restts obtained grown 4th instar larvae showed that tredtment of the 4th with CISs revealed many ultrastructural alterations in the midgut of the 6th instar larva. These alterations appeared clearly in the cytoplasm, the nuclei and cell organelles. The histology and ultrastructure of the alimentary canal, and the mid gut in particular have revealed various effects of tow tested CSIs. Obtained results indicated that CSIs could be good substitutes for traditional chemical insecticides for controlling S. littoralis due to their effect on midgut epithelial cells which may lead to malnutrition and eventually death.

Preparation and Characterization of Size-Controlled Nanoparticles for High-Loading λ-Cyhalothrin Delivery through Flash Nanoprecipitation.

Environmental concerns and low efficacy pose a challenge for the application of traditional insecticide formulations. In this study, a series of λ-cyhalothrin (LC)-loaded nanoparticles (NPs) were produced by flash nanoprecipitation (FNP), and the parameters that influence nanoparticle size were systematically studied. The narrowly distributed and size-controllable NPs formed stable suspensions in aqueous solution without organic solvents. The amphiphilic block polymer PEG-PDLLA played an important role as a drug carrier, and the encapsulation content was as high as 99%. The obtained NPs with high loading of LC exhibited toxicity comparable to those of two commercial formulations at low doses. This confirms that FNP technology is a promising and scalable method for agrochemical delivery.

Histopathological Changes in the Muscle of the Desert Locust, Schistocerca gregaria (orthoptera: acrididae)Treated with Insect Growth Regulator (IGR), Lufenuron

The present study aimed to minimize the pollution effects of traditional insecticides on the environment by development and synthesis of bio-insecticide and to evaluate insect growth regulators , Lufenuron as insecticidal agents. Stock colony of Schistocerca gregaria was used in this study which were kept in cages and fed on leaves of Castor plant. Treatment of the fifth nymphal instar of locusts by using insect growth regulator, Lufenuron were carried out. Results showed that, the treatment with different concentrations of Lufenuron (50, 75 and 100 ppm) resulted in nymphal mortality of 0.0, 12.33 and 21.01% respectively and percentages of adult malformed with 89.99, 73.34 and 72.33 respectively comparing with control. The current study showed that Lufenuron caused malfunction and decomposition of the components in the muscles of the desert locust.

Monitoring and biochemical characterization of beta-cypermethrin resistance in Spodoptera exigua (Lepidoptera: Noctuidae) in Sichuan Province, China

The beet armyworm Spodoptera exigua, a major pest affecting numerous cultivated crops in China, has developed a serious resistance to many traditional chemical insecticides. The resistance levels of the field-collected populations from different districts in Sichuan Province, China, to nine insecticides were detected with a diet-incorporation bioassay. Compared to the Lab-ZN strain, five (in 2014) and three (in 2016) field populations displayed either high or extremely high levels of resistance to beta-cypermethrin. All the field populations collected in 2014 were susceptible to emamectin benzoate, hexaflumuron, methoxyfenozide, chlorantraniliprole, cyantraniliprole and indoxacarb but exhibited low or moderate levels of resistance to abamectin. The resistances of field populations collected in 2016 were significantly higher than two years earlier, especial for chlorantraniliprole and cyantraniliprole with RRs rising from 173.4- to 582.6-fold and 175.3- to 287.6-fold, respectively, even though the field populations had retained moderate or low levels of resistance to chlorpyrifos and hexaflumuron. The synergism experiment revealed that the resistance of the LS16 population to beta-cypermethrin may be mainly related to cytochrome P450 monooxygenases (P450s), which was responsible for the highest increase ratio of 37.97-fold, for piperonyl butoxide, rather than either carboxylesterase (CarE) or glutathione S-transferase (GST). The cytochrome P450 ethoxycoumarin O-deethylase activity of the LS16 population was also the strongest among the treatments (P < 0.05). Non-denaturing polyacrylamide gel electrophoresis (native PAGE) indicated that enhanced E11, E13 and E15-E16 bands in the LS16 population likely contribute to the development of resistance to beta-cypermethrin.

Low Environmental Impact Method for Controlling the Peach Fruit Fly, Bactrocera zonata (Saunders) and the Mediterranean Fruit Fly, Ceratitis capitata Wied.), in Mango Orchards in Egypt

AbstractThe study was carried out at two experimental farms in Ismailia Governorate, Egypt, during season of 2015 and 2016. GF-120 (Conserve®0.024% CB) was selected in this study to evaluate its efficacy for controlling the peach fruit fly,Bactrocera zonata(Saunders) and the Mediterranean fruit fly,Ceratitis capitata(Wied.), on mango fruits by using partial bait spray and spots method. GF-120 was used as low environmental impact method and new way to controlB. zonataandC. capitata, compared with malathion 57%, as traditional insecticide. During both seasons, data revealed that the number ofC. capitatacaptured weekly from different treatments and untreated plots was higher than the number ofB. zonatacaptured in both seasons of experiment. Data revealed that the number males ofB. zonataandC. capitatacaptured weekly from sticky traps were lower in trees treated with GF-120 than malathion and untreated plots. In the farm of Faculty of Agriculture, Suez Canal University, the lowest percentages of infestation of both dropping and setting fruits per tree were recorded in plots treated with GF120 (spots), with an average of 25.14 and 17.022% for dropping fruits and 2.2 and 2.0% for setting fruits for 2015 and 2016 season, respectively. Data indicated that the all tested formulation under field condition caused significant reduction in the rate of infestation from 54.92 to 81.79 for both dropping and setting fruits. The lowest percentages of infestations in the private farm of both dropping and setting fruits per tree were recorded in GF-120 (spray treatment), with an average of 20.0, 12.12 for dropping fruits and 3.4 and 4.0 for setting fruits for 2015 and 2016 seasons, respectively.

Sublethal effects of sulfoxaflor on biological characteristics and vitellogenin gene (AlVg) expression in the mirid bug, Apolygus lucorum (Meyer-Dür)

The mirid bug, Apolygus lucorum (Meyer-Dür) has evolved the resistance towards some traditional insecticides, especially pyrethroids and organophosphates. Sulfoxaflor, as a novel insecticide, is used for control of sap-feeding insects, like A. lucorum. Therefore, it is necessary to determine the acute toxicity and the potential sublethal effects of sulfoxaflor in A. lucorum. Here, the LD50 value of sulfoxaflor against A. lucorum was assayed as 3.347ng/adult at 48h via topical application. Besides, the effects of a sublethal dose (LD15) of sulfoxaflor on biological characteristics of A. lucorum were estimated by comparison of the life table parameters. The longevities and fecundity of parent generation did not exhibited significant difference between both control and treatment groups after exposure to LD15 dose of sulfoxaflor (0.568ng/adult) for 48-h. However, the parameters reflecting their progeny G1 generation population dynamics, including the intrinsic rate of increase (ri), the finite rate of increase (λ), the mean generation time (T), the net reproductive rate (R0) and gross reproduction rate (GRR) significantly reduced in the treatment group compared to the control. Furthermore, the expression level of AlVg mRNA significantly decreased by 43.8% in the progeny whose parents were treated with LD15 dose of sulfoxaflor in comparison with the control transgenerational female adults. These results suggested that sublethal dose of sulfoxaflor adversely affect the development and reproduction of transgenerational A. lucorum. The downregulation of AlVg might have negative impacts on the fecundity of A. lucorum.

Residual activity of diamide insecticides for Ostrinia nubilalis control in processing snap bean

The processing snap bean industry views European corn borer, Ostrinia nubilalis (Hübner), larvae as contaminates in beans and has established a near zero tolerance. Currently, growers in New York (USA) apply 1–2 pyrethroid insecticide treatments for O. nubilalis control in snap bean. The objective of this study was to compare the residual efficacy of diamide and traditional pyrethroid insecticides at various foliar application timings against O. nubilalis. Insecticides were tested at four different timings (1, 7, 10, and 14 days before snap bean pod formation) in field trials performed in western New York in 2015 and 2016. Treatments were evaluated for O. nubilalis plant and pod damage and yield. Bioassays using snap bean leaves collected from the treated field plots were used to assess larval mortality. All materials exhibited excellent control of O. nubilalis when applied 1 day before pod formation, reducing pod and plant damage to ∼0%. However, for applications 14 days before pod formation, chlorantraniliprole and chlorantraniliprole + lambda-cyhalothrin consistently had lower pod and plant damage and higher larval mortality compared with the other materials. Chlorantraniliprole applied at 7, 10, and 14 days before pod formation also resulted in higher yields than the untreated control in 2015. Our results indicate that chlorantraniliprole-containing insecticides could be applied only once per season, eliminating the need for multiple applications, and could also be co-applied with fungicides or herbicides, which are applied earlier than standard pyrethroid insecticides. These results indicate that the anthranilic diamides, especially chlorantraniliprole, exhibit longer-term efficacy than pyrethroids, increasing the flexibility of spray timing by growers.

Resistance Monitoring for Eight Insecticides on the Sweetpotato Whitefly (Hemiptera: Aleyrodidae) in China.

The sweetpotato whitefly, Bemisia tabaci (Gennadius), is an important pest of many crops worldwide. Because control of B. tabaci still depends on the application of insecticides in China, monitoring the insecticide resistance of B. tabaci populations is essential for achieving control and for managing resistance. In this study, field populations of B. tabaci on vegetables were collected in three regions of China in 2011, 2012, and 2013. The resistance of these populations (all of which were determined to belong to biotype Q) to eight insecticides (abamectin, spinetoram, imidacloprid, thiamethoxam, acetamiprid, nitenpyram, chlorpyrifos, and bifenthrin) was assessed by the leaf-dip method. No resistance to abamectin and spinetoram was detected. All of the B. tabaci populations exhibited resistance to neonicotinoid insecticides; the resistance was 3.6- to 125.0-fold greater than that of a susceptible reference strain. The traditional insecticides chlorpyrifos and bifenthrin had very low toxicity. Bemisia tabaci specimens in some regions exhibited annual differences in resistance to some of the insecticides. The data presented will be helpful for making decisions on the proper insecticide usage in the field.

Toxicity of A Novel Neonicotinoid Insecticide Paichongding to Earthworm Eisenia fetida

ABSTRACTTraditional neonicotinoid insecticides are used worldwide. Paichongding (IPP), as a novel neonicotinoid pesticide, has been widely used in China. However, the ecotoxicity of IPP to non-target invertebrates in soil ecosystem has not been reported yet. In this study, acute toxicity of IPP to earthworm Eisenia fetida, as well as the antioxidant response after IPP exposure, was evaluated. In the filter paper contact test, the LC50 at 24 hr and 48 hr for IPP were 14.98 μg/cm2 and 7.59 μg/cm2, respectively. In artificial soil test, the LC50 (lethal concentration) at 14 days and 28 days for IPP were 541.07 mg/kg and 238.51 mg/kg, respectively. The LC50 of IPP is much higher than that of traditional neonicotinoid insecticides. However, earthworm body weight assessment demonstrated that the growth of earthworm was inhibited by extended exposure to IPP at sublethal doses. The activities of antioxidative enzymes superoxide dismutase and catalase in earthworms were significantly induced after IPP exposure. Malondialdehyde, a biomarker of lipid peroxidation, was also increased after IPP exposure. Although the results indicated that IPP had potentially adverse effect on earthworms, its toxicity was much lower than traditional neonicotinoids.