Experimental Insecticides Research Articles

Polygenic, autosomal, and stable spirotetramat resistance in Chrysoperla carnea resulting in increased fitness.

Green lacewing, Chrysoperla carnea (Stephens) is a generalist predator used as a biological control agent in agro ecosystems. In order to use chemical and biological control in an integrated way, it is advantageous to know about natural enemy resistance response to a selected chemical. To determine C. carnea spirotetramat resistance potential, a population collected from the field was selected in the laboratory. Then we determined how spirotetramat resistance was inherited and how much it impacts the fitness of C. carnea. After eighteen selections with spirotetramat, the selected population (Spiro-Sel) of C. carnea had a 47-fold of resistance when compared to an UNSEL population. Inheritance results showed that spirotetramat resistance was inherited as an autosomal, incompletely dominant and polygenic trait. The values of effective dominance decreased from 0.87 (incomplete dominant) to 0.00 (complete recessive) as the concentration of spirotetramat increased from 625 mg/L to 10000 mg/L. The Spiro-Sel strain had no cross resistance to chlorfenapyr (1.10-fold), deltamethrin (1.26-fold) and chlorpyrifos (1.27-fold). After 7 generations without selection pressure resistance to all experimental insecticides in the Spiro-Sel strain was stable. Fitness data of the Spiro-Sel, Cross A, Cross B, UNSEL and susceptible strains of C. carnea showed that spirotetramat resistance increased the fitness of the selected green lacewing population. Life history parameters like fecundity, net reproductive rate, and relative fitness of the Spiro-Sel strain significantly increased when compared to the susceptible or unselected strains of C. carnea. These findings show that C. carnea is a perfect candidate for integrated pest management (IPM) programmes that combine biological control methods with selective pesticide applications to manage a variety of insect pests. Additionally, it would reduce the possibility of pests developing pesticide resistance despite repeated applications. It would be an excellent choice for widespread releases and be effective in most spray programs.

Biophoton emission-based approach of the effects of systemic insecticides on the survival of Eurydema ventralis Kolenati, 1846 (Hemiptera: Pentatomidae) and on the photosynthetic activity of oilseed rape

The choice of effective crop protection technologies is a key factors in the economical production of oilseed rape. Insecticides belonging to the group of active substances butenolides and diamides are active substances available as seed treatments in oilseed rape and promising control tools in the crop protection technologies. Our laboratory experiment demonstrated that the experimental insecticides flupyradifurone and cyantraniliprole are both effective against Eurydema ventralis (Hemiptera: Pentatomidae) when used as a seed and in-crop treatments, but there is a fundamental difference in their insect mortality inducing effects. Flupyradifurone was found to have a total mortality 96 h after application based on basipetal translocation. In the case of cyantraniliprole, the insecticidal effect of the same treatment was 27% less. The experiment showed that the acropetal translocation of the tested active substances after seed treatment did not induce efficacy comparable to that of the basipetal translocation. The study of the biophoton emission of the plants demonstrated a verifiable correlation between the different application methods of the insecticides and the photon emission intensity per unit plant surface area. In conclusion, the systematic insecticides tested, in addition to having the expected insecticidal effect, interfere with plant life processes by enhancing photosynthetic activity.

Can Insects Assess Environmental Risk? Movement Responses and Nymph Emergence in Response to Insecticides

In natural habitats, there is a strong evolutionary selection pressure on herbivorous insects to avoid danger and choose suitable host plants. Similar selection pressures may drive movement and choices of oviposition hosts by herbivorous insects living in agricultural cropping systems, in which insecticides are often used. In this study, we quantified movement responses and nymph emergence (collectively referred to as bio-responses) of western-tarnished plant bug (Lygus hesperus Knight (Hemiptera: Miridae)) individuals when exposed to environments associated with a perceived “risk” (experimental insecticide treatments and their corresponding controls). We introduce a novel analytical approach in which treatments (risk environments) are ranked in ascending order based on bio-responses (movement or nymph emergence). Consequently, linear regression coefficients were generated and used to interpret bio-responses of Lygus individuals in different life stages to risk environments. Initially, we predicted movement by Lygus individuals to be positively associated with environmental risk and nymph emergence to be negatively associated with environmental risk. Overall, based on a comprehensive combination of no- and two-choice bioassays, we found that: (1) In no-choice bioassays, movement parameters (both total distance moved and movement percentage) by all three life stages were lowest in low-risk environments and highest when Lygus individuals were exposed to either malathion or Grandevo. Accordingly, environments involving malathion or Grandevo were considered high-risk. (2) No-choice movement bioassays also revealed that Lygus males moved significantly more (based on comparison of regression intercepts) than other life stages, and that they responded significantly more (based on comparison of regression slopes) than conspecific females and nymphs. (3) In two-choice movement bioassays, neem elicited the most consistent movement responses by Lygus individuals, and adult life stages showed the strongest response. Two-choice movement bioassays also revealed that Lygus adults, compared to nymphs, were more likely to spend time in low-risk areas of the test arenas. (4) Nymph emergence was markedly lower in no-choice compared to two-choice bioassays, and in two-choice bioassays, Grandevo and malathion elicited especially biased nymph emergence from low-risk beans. To our knowledge, this is the first study in which movement bioassays have been used to quantify and characterize behavioral responses by Lygus life stages to environments associated with varying degrees of risk. The novel analytical approach presented in this study provides a high degree of complementarity to more traditional performance-testing methods used to evaluate responses to insecticides. Furthermore, we believe that this analytical approach can be of considerable relevance to studies of animal phenomics and behavioral studies of animals more broadly, in which adaptation and fitness parameters are examined in response to environmental risk and heterogeneity.

Control of fall armyworm with labeled and experimental insecticides in sweet corn, spring 2023

Control of fall armyworm with labeled and experimental insecticides in sweet corn, spring 2023

Evaluation of experimental insecticides and biopesticides for control of southern armyworm (SAW) on staked tomato in Southwest Florida, 2022

Evaluation of experimental insecticides and biopesticides for control of southern armyworm (SAW) on staked tomato in Southwest Florida, 2022

Experimental insecticide applications change tomato pollinator assemblages and do not increase fruit production

One of the main threats to pollinators is insecticide application, many products widely used have lethal and sub-lethal (affects behavior, health, and fitness) effects on pollinators, and hence pollination. As sensitivity to such effects varies across species, insecticide application also changes the pollinator community composition within agricultural landscapes and hence affects the assemblages of crop pollinators. However, studies on the effects on native bees and their consequences on pollination services are lacking for many pesticides. Here, we use an experimental setup placed in four study regions (each with three blocks, with 15 experimental per block) to evaluate the effect of lambda-cyhalothrin pulverization on pollination and production of tomato (Solanum lycopersicum L.). Lambda-cyhalothrin is a pyrethroid insecticide highly toxic to the environment and commonly used in the tomato crops of Brazil, a crop that is pollinated by a diverse community of native bees. The effect of an alternative insecticide, classified as biological, on pollinators and pollination of tomatoes was also evaluated. For each experimental individual under each treatment, we collected data on the pollinator visitation before and after starting pulverization up to 23 days after the last application of pesticides. We also evaluated the effect of the three treatments on stigma pollen load, fruit, and seed production. We found that in all treatments (even control) visitation rate was higher before than after pulverization. During the spraying period, the plants sprayed with pyrethroid insecticide showed lower pollinator visitation compared to other treatments, these plants also ended with lower pollen deposition on the stigma. Paratrigona lineata was more susceptible to insecticide pulverization than other bee species. Recovery of visitation rates was detected after 23 days for all treatments. Despite the effect on visitation and pollen deposition, fruit and seed sets were similar among treatments. Overall, our results show that pyrethroid insecticide pulverization causes changes in the behavior of native flower-visiting bees. The mechanisms that explain these changes deserve further investigation, and further studies are needed to understand the large-scale effects of the use of pyrethroid insecticide on insect biodiversity and agricultural landscapes. As the biological insecticide had lower negative effects on bees, future studies that take into account both the effects on pest damage and pollination are needed to define more sustainable management approaches, minimizing negative impacts on biodiversity.

Development of Methods for the Use of Aphid Alarm and Mite Aggregation Pheromones

The purpose of this work was to develop effective methods of protecting fruit crops based on the use of aphid alarm and mite aggregation pheromones. The study was conducted in 2020-2021 on a private farm in the Krasnodar Territory. Laboratory studies were carried out on two types of aphids: Aphis pomi Deg. and Myzus cerasi F. with the use of trans-beta-farnesene where crushed aphids of the tested species served as the source of the alarm pheromone, and insects without treatment were used as a control group. Field tests were carried out on registered trees with aphid colonies up to 10% of shoots in the crown, and mite colonies of 15-23 specimens/ leaf. Significant differences in the types of ethological reactions of apple and cherry aphids to trans-beta-farnesene were observed. In A. pomi, the predominant type was the twitching of the body during the initial period of exposure to the semiochemical. In cherry aphids, only one type of behavioral reaction to the alarm pheromone was noted, namely leaving the feeding site. The results of testing trans-beta-farnesene compositions with preparations based on biorational active substances, Phytoverm CE (2 g/l), and experimental insecticides based on coriander essential oil indicate the prospects of using the aphid alarm pheromone (trans-beta-farnesene) to increase the effectiveness of anti-aphid insecticides. Similar results were obtained in tests of trans-nerolidol, the pheromone used for aggregation of red spider mites in a composition with the Apollo, SC acaricide (500 g/l).

Control of Fall Armyworm With Labeled and Experimental Biopesticides Insecticides in Sweet Corn, Spring 2021

Control of Fall Armyworm With Labeled and Experimental Biopesticides Insecticides in Sweet Corn, Spring 2021

Experimental Insecticide Applications in Corrected Dosage Changes Tomato Pollinator Assemblages and Does Not Increase Fruit Production

Experimental Insecticide Applications in Corrected Dosage Changes Tomato Pollinator Assemblages and Does Not Increase Fruit Production

Control of Fall Armyworm With Labeled and Experimental Biopesticides and Insecticides in Sweet Corn, Fall 2020

Control of Fall Armyworm With Labeled and Experimental Biopesticides and Insecticides in Sweet Corn, Fall 2020

Side effects of two citrus essential oil formulations on a generalist insect predator, plant and soil enzymatic activities

The widespread use of chemical pesticides for crop protection, despite having contributed to ensure food security, have shown to exert negative impacts on the environment and on human health. In addition, the frequent emergence of resistance to pesticides and their adverse effects toward non-target organisms have generated the need to develop novel ecofriendly tools for pest control. Among these, plant essential oils (EOs) may play a central role in arthropod pest control. Recently, two formulations (Emulsion and PEG-nanoparticles) of three citrus EOs (lemon, mandarin and sweet orange) showed a promising potential against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a key tomato pest. Here, we evaluated the side effects of these experimental insecticides active substances toward (i) the generalist predator of several tomato pests, Nesidiocoris tenuis Reuter (Hemiptera: Miridae); (ii) the soil enzymatic activities (dehydrogenase activity, alkaline phosphomonoesterase, acid phosphomonoesterase and urease) and (iii) the tomato plant antioxidant enzymes (ascorbate peroxidase, catalase, superoxide dismutase and polyphenol oxidase). Among the tested formulations, mandarin EO-based insecticide presented a significant impact on the predator survival and reproduction. Conversely, all the tested compounds proved to be harmless for the soil enzymatic and the plant antioxidant activities. Overall, these results provide solid bases for the development of novel biopesticides for sustainable tomato crop protection.

Foliar Sprays of Labeled and Experimental Insecticides to Control Asian Citrus Psyllid on Orange, Summer 2019

Foliar Sprays of Labeled and Experimental Insecticides to Control Asian Citrus Psyllid on Orange, Summer 2019

Foliar Sprays of Organically Labeled and Experimental Insecticides to Control Asian Citrus Psyllid on Orange, Summer 2019

Foliar Sprays of Organically Labeled and Experimental Insecticides to Control Asian Citrus Psyllid on Orange, Summer 2019

Assessing Insecticide Effects in Forests: A Tree-Level Approach Using Unmanned Aerial Vehicles

Large-scale field studies on the ecological effects of aerial forest spraying often face methodological challenges, such as insufficient funding, difficult logistics, and legal obstacles. The resulting routine use of underpowered designs could lead to a systematic underestimation of insecticide effects on nontarget arthropod communities. We tested the use of an Unmanned Aerial Vehicles (UAVs) for experimental insecticide applications at tree level to increase replication in cost-efficient way. We assessed the effects of two forestry insecticides, diflubenzuron (DFB) and tebufenozide (TBF), on the oak defoliator, Thaumetopoea processionea (Linnaeus) (Lepidoptera: Thaumetopoeidae), and on nontarget, tree-living Lepidoptera. Individual trees were sprayed with either insecticide or left unsprayed, in a fully factorial design involving 60 trees. Caterpillars fallen from tree crowns were sampled as a measure of mortality, while caterpillar feeding activity was monitored by collecting frass droppings. Both DFB and TBF led to greater mortality of T. processionea and lower Lepidoptera feeding activity than control levels. TBF caused measurable mortality in nontarget groups, affecting Macrolepidoptera more strongly than Microlepidoptera, while there was no significant side effect of DFB. The high treatment efficacy against the target pest indicates that UAV technology is well-suited for the application of insecticide in forests. We detected distinct responses to different insecticides among nontarget groups and suggest there is an influence of application timing and biological traits in these differences, emphasizing the need for more ecologically orientated risk assessment. UAV-supported designs can be used to link laboratory bioassays and large-scale experiments, allowing for more comprehensive assessments of insecticide effects in forest ecosystems.

Evaluation of Registered and Experimental Foliar Insecticides for the Control of Potato Aphid in Potato, 2018

Evaluation of Registered and Experimental Foliar Insecticides for the Control of Potato Aphid in Potato, 2018

Foliar Sprays of Labeled and Experimental Insecticides to Control Asian Citrus Psyllid and Citrus Leafminer on Orange: Summer, 2017

Foliar Sprays of Labeled and Experimental Insecticides to Control Asian Citrus Psyllid and Citrus Leafminer on Orange: Summer, 2017

Foliar Sprays of Labeled and Experimental Insecticides to Control Asian Citrus Psyllid on Grapefruit, 2017

Foliar Sprays of Labeled and Experimental Insecticides to Control Asian Citrus Psyllid on Grapefruit, 2017

Effects of an Insecticide Exposure Prevention Program on Exposure and Blood Cholinesterase Levels in Thai Farmers

OBJECTIVE: This Quasi-experimental research aimed at investigating the effects ofan insecticide exposure prevention program on exposure and blood cholinesteraselevels of farmers. MATERIALS AND METHODS: The conceptual framework was guided by theDonabedian and the RAMA models. Through convenience sampling with inclusioncriteria, the sample included 49 radish farmers exposed to Organophosphate consistingof an experimental group (n=25) and a control group (n=24). The experimental groupparticipated in a 12-week insecticide exposure prevention program that included:Raising awareness at the individual, family and community levels, Aiming at targetoutcome, Mobilizing change and innovation, and Assuring synergy involved homevisits and assessments by health teams. The control group received a guide book forfarmers and routine nursing care. The data were collected from April to July, 2016. Thedata were analyzed using Descriptive statistics and Inferential statistics including Pairedt-test, Independent t-test, Chi-square test, and Mann Whitney U test. RESULTS: The results revealed that after the program, the experimental group hadlower insecticide exposure level than the control group with statistical significance(p 0.05) and between the experimental group and the control group(p > 0.05). CONCLUSION: The results suggest that community nurse practitioners apply theprinciple of raising awareness, aiming at target outcome, mobilizing change andinnovation as approaches for the insecticide exposure prevention program in the“farmers’ health clinic”, along with outcome monitoring for sustainability.

Control of Diamondback Moth on Broccoli With Labeled and Experimental Insecticides, 2016*

Control of Diamondback Moth on Broccoli With Labeled and Experimental Insecticides, 2016*

Registered and Experimental Foliar Insecticides for Control of Colorado Potato Beetle and Potato Leafhopper in Potato, 2016*

Registered and Experimental Foliar Insecticides for Control of Colorado Potato Beetle and Potato Leafhopper in Potato, 2016*