Insecticide Solutions Research Articles

BIOLOGICAL PARAMETERS AND ENZYME ACTIVITIES IN MUSCA DOMESTICA UNDER SELECTION WITH FIPRONIL

Insect resistance to insecticides is one of the main issues of veterinary, medicine, and horticulture around the world. Knowledge of insecticidal resistance mechanisms is crucial for the development of insect control programs. The aim of the present study was to assess some biological parameters and enzyme activities in the house fly Musca domestica L. under selection with fipronil. The selection of M. domestica with fipronil was conducted by non-choice feeding when adults in each generation were fed with sugar that was pre-treated with insecticide solution. In even-numbered year generation, we evaluated the duration of individual development stages, the weight of individuals, fertility, and activity of the main detoxification enzymes (monooxygenases, esterases, and glutathione-S-transferases) in larvae and adults. The assessment of insect susceptibility to fipronil showed that larvae in the tenth generation of the fipronil-selected strain were more susceptible to fipronil than the individuals in the laboratory strain, and adults did not differ from the control as per this indicator. In the tenth generation of the fipronil-selected strain, we found that the duration of the development period from the egg stage to the emergence of adults lasted longer (by 18%) compared to the laboratory line. We noted that the activity of monooxygenases and glutathione-S-transferase in larvae and adults varied in certain generations of the fipronil-selected strain.

Examining the Relationship of Clinical and Laboratory Parameters With Infectiousness to Phlebotomus perniciosus and Its Potential Infectivity in Dogs With Overt Clinical Leishmaniasis.

Infected dogs are considered the main domestic animal reservoirs for Leishmania infantum parasite. Infectiousness to competent phlebotomine vectors has been associated with many factors, the main being the severity of the disease exhibited by infected dogs. This study examines the relationship between different clinical parameters and the infectiousness to colonized Phlebotomus perniciosus sand flies having a blood meal on dogs. Data obtained in the present study come from an untreated group of Leishmania sick dogs submitted to xenodiagnosis for the evaluation of a spot on insecticide solution. Seventeen dogs were diagnosed as affected by leishmaniasis through clinical examination, immunofluorescence antibody test (IFAT) serology, and loop-mediated isothermal amplification (LAMP). The disease severity (clinical score) was staged by using a numeric value derived from eight clinical and parasitological parameters. Xenodiagnosis was performed on caged dogs exposed for 1.5 h to sand-fly bites. The following parameters related to sand flies were examined: blood feeding (% of blood engorged females), promastigote detection (% of promastigote-positive sand flies), promastigote burden, and the promastigote stage maturation (potential transmissibility rate). Statistical relationship between the clinical score and entomological parameters was investigated, as well as the possible correlation between each clinical and laboratory parameters and sand fly infection/infectivity. The severity of clinical score may influence the blood feeding by, and the probability of promastigote detection in, sand flies; skin lesions seem to be the main factor that influences the rate of blood feeding. Promastigote burden is related to IFAT titer, skin lesions, and clinical score. All entomological parameters are strongly related among them. This study confirms that both P. perniciosus infection and infectivity are influenced by a dog's clinical condition.

Phytophagous energy plantings of willow

Purpose. Investigation of the species composition and the number of plant feeders in energy willow plantations.
 Method. Field, accounting, statistical, analytical.
 Results. Today, growing plants for the production of biofuels is a promising source of energy that have a high potential for energy recovery. Biomass of energy crops such as willow is a renewable energy source with zero balance of carbon dioxide and methane. Fast-growing trees such as willow are perennials that are able to produce biomass over a long period. However, like any plant, willow is a host tree for many living organisms, including insects. According to the results of our observations and records, among the latter, this crop is damaged by both soil and land plant feeders. Of the soil pests, the most dangerous for willow are the larvae of several species of May beetles, which feed on the roots causing significant inhibition of growth and development of plants or even their death. The number of these insects per square meter in different zones ranges from 0.6–0.8 to 1.6–1.9. In the focuses, the population density of the larvae per square meter reaches 8.8. In addition to beetle larvae, the root system of willow is damaged by the larvae of click beetles, Elatericlae, Blaps and Anisoplia austriaca larvae. The number of these larvae per square meter ranges between 0.8 and 2.3 and between 0.5 and 2.7, respectively. Of land pests, willow is damaged by Chrysomela saliceti (0.7–7.2, in focuses 3.2–22.0 pests/plant), willow aphid (population score 1.1–1.8, in focuses 1.7–2.3), Hyponomeuta malinellus (population ratio 1.1–1.2, in focuses 1.8–2.1), Leucoma salicis (0.2–0.3, in focuses 1.9–6.1 larvae/plant), Chionaspis salicis (0.7–1.0, in focuses 2.3–10.0 individuals), Tetranychus urticae (population score 1.0–1.3, in focuses 1.4–2.3) and Philaenus spumarius, (0.1–0.8 in focuses 1.0–3.4 pests/plant). The control of the number of these plant feeders is carried out by soaking of cuttings before planting in insecticide solutions, as well as spraying the plants with chemicals against land pests.
 Conclusions. Energy willow plants are damaged by many species of soil and land plant feeders, the number of which depends on the area of growing. Controlling of their number is carried out by soaking cuttings before planting in insecticide solutions and spraying plants.

Anti-resistant plant protection system against harmful arthropods

Goal. To substantiate and develop an anti-resistant system of protection of crops and perennials from harmful arthropods.
 Methods. The sensitivity of phytophages on natural populations collected on winter wheat, soybean, and rapeseed crops was determined by various methods of their poisoning: immersion of insects on inhabited plants, immersion of insects in gauze bags for 3 seconds. in a suitable solution of insecticide. The methods are based on the study of the pest’s response to a series of doses of the drug — from the minimum, causing mortality of 5—10% of normal-sensitive individuals, to the maximum (mortality of 90% or more). Toxicological parameters were calculated using the PROBAN program.
 Results. Different sensitivity of natural populations of arthropods to modern insecticides is revealed. Techniques for the rational use of insecticides populations and the use of alternative biological and immunological methods.
 Conclusions. An effective measure to prevent and inhibit the formation of resistant populations of harmful arthropod species to insecticides is an anti-resistant plant protection system. It includes monitoring the resistance of natural populations of harmful phytophagous species, identifying the type of resistance and the rational use of chemicals.

Corrosion Resistance of Steel of the Frames of Boom Sprayers

We perform the comparative analysis of the corrosion resistance of St3ps steel in demineralized water and in saturated solutions of the Nurelle-D insecticide and UN-32 complex liquid fertilizer. It is shown that, in demineralized water, the general corrosion of the steel surface is predominant. In a solution of insecticide, parallel with general corrosion, we observe a partial realization of pitting corrosion. In a medium of mineral liquid fertilizer, we observe the passivation of the metal surface caused by phosphorus-containing corrosion inhibitors, which leads to the inhibition of the general corrosion. However, local violations of the passive state of the metal surface lead to the intense formation of corrosion pits, which is dangerous due to the possibility of their development accompanied by the initiation of cracklike defects in the structures.

Physiological quality of soybean seeds treated with imidacloprid before and after storage

This study aimed to evaluate the effect of different slurry volume of imidacloprid insecticide on the physiological potential during the storage of seeds of three soybean cultivars. A completely randomised experimental design was adopted, in a 6 × 3 × 2 factorial scheme, which treatments were six slurry volumes with imidacloprid insecticide (0, 200, 500, 800, 1 100 and 1 400 mL/100 kg of seeds), 3 soybean cultivars (SYN15630, M5947, and NS5959) and 2 storage periods (0 and 30 days after seed treatment), with four replications. The treated seeds were stored in kraft paper bags with controlled temperature and humidity. The physiological potential of the seeds was evaluated by standard germination test, electrical conductivity, accelerated aging, seedling emergence in the sand seedbed, and the field. The germination and vigor of soybean seeds were reduced during storage, especially with the increase in the volumes of the insecticide solution.

Synergism and unintended effects of the association between imidacloprid and sodium chloride (NaCl) on the management of Euschistus heros.

The use of insecticidal solutions containing sodium chloride (NaCl) has been proposed as a more environmentally friendly alternative to managing stink bug infestations of Neotropical soybean fields. The potential sublethal and undesirable effects of this practice have, however, been overlooked, especially with novel insecticides. Here, we have evaluated experimentally whether the addition of NaCl (0.5% w/v) to imidacloprid-containing solutions could alter insecticide toxicity and modify the reproductive responses of the Neotropical brown stink bug Euschistus heros. Adding NaCl to imidacloprid solutions significantly increased imidacloprid toxicity against E. heros. The exposure to E. heros to sublethal concentrations of imidacloprid affected the insect's mating abilities in a concentration-dependent manner. The addition of NaCl to solutions containing imidacloprid at concentrations as low as 0.126 μg a.i. cm-2 (i.e. the equivalent to 3% of field rate recommendation) also impacted the sexual behavior of E. heros, reducing mating duration. NaCl-exposed stink bugs, however, exhibited higher fecundity and fertility rates than those insects that were unexposed to NaCl or those that were exposed to sublethal levels of imidacloprid only. The addition of low amounts of NaCl resulted in a higher toxicity of imidacloprid. This practice, however, can also lead to undesirable effects as increasing reproductive output of E. heros that can potentially compromise the management of these insect pests.

Effect of chlorination on anti-acetylcholinesterase activity of organophosphorus insecticide solutions and contributions of the parent insecticides and their oxons to the activity

Organophosphorus insecticides are known to be partly transformed to their respective oxons during the chlorination step of drinking water treatment. For most organophosphorus insecticides, the toxicological endpoint for determining acceptable daily intake levels is inhibition of acetylcholinesterase (AChE). Like the parent insecticides, oxons also inhibit AChE, so the presence of oxons in drinking water is also evaluated. However, no attention is paid to the possible presence of transformation products (TPs) other than oxons. In the present study, we determined whether the anti-AChE activity observed for chlorinated solutions of the organophosphorus insecticides malathion and methidathion could be solely attributed to the parent compounds and their oxons. Upon chlorination, both malathion and methidathion were immediately transformed to their oxons; the maximum transformation ratios were 60% and 30%, respectively, indicating that at least 40% and 70% of these compounds were transformed into other TPs. Before chlorination, malathion- and methidathion-containing solutions exhibited little to no anti-AChE activity, but the solutions showed strong activity after chlorination. The contributions of the parent insecticides and their oxons to the activities of the chlorinated samples were calculated from the concentrations of the compounds in the samples and dose–response curves for chemical standards of the compounds. For both the malathion-containing solution and the methidathion-containing solution, the calculated anti-AChE activities were almost the same as the observed activities at every chlorination time. This suggests that the observed activities could be attributed solely to the parent insecticides and their oxons, indicating that other TPs need not be considered.

Comparison of the efficacy of two insecticides for the management of Dactylopius opuntiae on prickly pear cactus in Lebanon and monitoring of the insecticides residues dissipation rates in fruits and cladodes

Environmental conditions and availability of new cultivated areas of prickly pear cactus in Lebanon appeared lately to be favourable for the survival and development of D. opuntiae which has become highly noxious. To thwart use of random chemicals and broad spectrum pesticides by local farmers, efficacy of sulfoxaflor (Closer™ 240 SC, rate 0.179 kg a.i/ha) and diflubenzuron (Dimilin® 25 W, rate 0.329 kg a.i/ha) was compared. Individual insecticidal solutions of each applied alone or in mixing with mineral oil (spray oil 7E, rate 1.010 kg a.i/ha) on potted cladodes in laboratory conditions (T = 23 ± 4 °C, RH = 58–63%) showed a sharp decrease in the number of individuals within colonies 48 h after treatment especially among first- and second-instar larvae. Similarly, the same insecticidal solutions applied on separate plots in field conditions (T = 20–35 °C, RH = 55–75%) according to the Good Agricultural Practices showed efficacious control of the pest development. D. opuntiae mortality mean percentage reached 80% and 72%, respectively, for sulfoxaflor and diflubenzuron 96 h after treatment. The added mineral oil acted as a synergist and enhanced efficacy of both insecticides. Mortality mean percentages increased to 92% and 88%, respectively. Insecticides residues content over time in fruits and cladodes were afterwards monitored. Samples were harvested at 3 days interval and residues extracted by the QuEChERS method and quantified by LC–MS. Dissipation rates after 30 days of treatment attained 70.8% and 80.6% in fruits and 98.5% and 74.0% in cladodes, respectively, for sulfoxaflor and diflubenzuron. Half-life time varied accordingly and was higher for fruits treated with sulfoxaflor (14.20 days) than for those treated with diflubenzuron (11.18 days). On contrary, for cladodes, half-life time of the former (4.18 days) was lower than that of the latter (15.47 days). The addition of mineral oil into the spray solution of the insecticides increased their persistency in the crop. Consequently, half-life times increased and dissipation rates decreased. Findings of this study should enlarge the spectrum of chemical means for D. opuntiae management and promote resilience of the crop. Analytical method applied for residues analysis should be useful for registration of the insecticides on the crop and MRLs setting.

Leaching of insecticides used in blueberry production and their toxicity to red worm.

Soil columns were collected from a blueberry field, and insecticide solutions were allowed to leach through these columns. Insecticides from four different chemical classes were applied at two different rates: the concentration at which the insecticides wash off blueberries under rainfall conditions and the labeled field rate at which they are sprayed. The soil columns were divided into thirds; top, middle and bottom. Soil bioassays using Eisenia foetida Savigny, as an indicator species, were set up to determine the toxicity of the insecticides at a top, middle and bottom layer of the soil column. The mass of E.foetida was also measured after the bioassay experiment was completed. The concentrations at which insecticides wash-off of blueberries from rainfall were not lethal to E.foetida. In order to support mortality data, insecticide residues were quantified in the soil layers for each insecticide. Under field rate leaching conditions, carbaryl showed the high levels of toxicity in the top and middle layers of soil suggesting that it has the highest risk to organisms from leaching. This study will help blueberry growers make informed decisions about insecticide use, which can help minimize contamination of the environment.

Tank mixture of pesticides and foliar fertilizers for Triozoida limbata control in guava trees (Psidium guajava L.)

ABSTRACT Although tank mixture of pesticides and foliar fertilizers is common practice in agriculture, further clarification and scientific evidence is needed to support regulation. Thus, the objective of this work was to evaluate the effect of tank mixing an organosilicon adjuvant and manganese foliar fertilizer on the insecticide imidacloprid effectiveness against Triozoida limbata in guava trees. The experimental plot consisted of four consecutive trees in the same row subdivided into 4 quadrants. The experiment was arranged in a randomized block design with split plots, with four replications. Treatments were as follows: T1 - Imidacloprid (Imid.); T2 - Imid. + Polyether-polymethyl siloxane copolymer (Sil.); T3 - Imid. + MnSO4; T4 - Imid. + Sil. + MnSO4; and T5 - Control (no application). Physical-chemical characteristics, spray deposition on the leaves and losses to the soil, guava psyllid percentage of infestation and nymph’s number were evaluated. The addition of foliar fertilizer into the mixture decreased the pH and the surface tension and increased the electric conductivity and the viscosity of the insecticide solutions. The silicon adjuvant decreased the surface tension and increased the viscosity and the pH. The tank mixture of organosilicon adjuvant and manganese foliar fertilizer has no influence on the efficacy of the insecticide.

Toxic Activity of Pyrethroids in <i>Lutzomyia longipalpis</i> (Diptera: Psychodidae) from Magdalena River Basin, Colombia

The study aimed to determine the toxicity of lambda-cyhalothrin, alpha-cypermethrin, and deltamethrin in L. longipalpis, through concentration-mortality bioassays. The test here was performed following WHO guidelines, but instead of using exposure WHO recipients and impregnated papers, 250 ml Wheaton glass bottles treated with 1 ml of insecticide solution were used. Batches of ten females of L. longipalpis were exposed to five concentrations of each pyrethroid that caused between 5 and 100 % mortality in this species. After 1 h of exposure, the females were transferred to observation recipients, and mortality was recorded 24 h later. The lethal concentrations (μg/ml) that killed 50 and 95 % (LC50 and LC95) of the exposed L. longipalpis females were 0.05 and 0.86 for lambda-cyhalothrin, 0.24 and 3.62 for alpha-cypermethrin and 0.53 and 4.72 for deltamethrin. Based on the LC50 obtained, lambda-cyhalothrin is the most toxic pyrethroid for L. longipalpis, followed by alpha-cypermethrin and deltamethrin. It is expected that these data may be useful in studies on the effects of sub-lethal concentrations of the three pyrethroids on the behavior of L. longipalpis and studies on the vector susceptibility to these pyrethroids.

Larvicidal activity of spinosad and its impact on oviposition preferences of the West Nile vector Culex pipiens biotype molestus – A comparison with a chitin synthesis inhibitor

In the present study, the larvicidal activity of ageing aqueous suspensions of spinosad against larvae of Culex pipiens biotype molestus, as well as their effect on the oviposition preferences of adult gravid females were evaluated in laboratory bioassays. Spinosad was applied at its label dose and the aqueous stock suspensions were stored for various ageing intervals up to 38 days. Untreated distilled water and diflubenzuron served as negative and positive control, respectively. Stock suspensions were taken after 0, 2, 6, 8, 16, 30 and 38 days of storage for diflubenzuron and after 0, 2, 6, 8, 20 and 27 days for spinosad, and were used for the bioassays. Furthermore, the effect of spinosad on the oviposition response of Cx. p. biotype molestus gravid females was investigated in two-choice oviposition preference bioassays. Spinosad was evaluated at half of its label dose and at its label dose, whereas diflubenzuron and distilled water served as positive and negative control, respectively. Results showed that both insecticides were found highly effective for the control of Cx. p. biotype molestus larvae, for ageing intervals up to 27 and 38 days for spinosad and diflubenzuron, respectively. Spinosad acted immediately after the preparation of the insecticidal solution (LT50 = 1.5 h), whereas for aged samples, LT50 values increased with the increase of the ageing interval (LT50 = 5 days for the 27 days old sample). For diflubenzuron, ageing time increased its insecticidal activity, as for aged diflubenzuron-treated solutions, lower LT50 values were achieved. In the oviposition preference bioassays, significantly fewer egg rafts were laid in water treated with spinosad at its label dose compared to control. However, this was not the case for water treated with spinosad at half of its label dose. Oviposition Activity Index (OAI) values were always comprised between −0.3 and 0.3, showing no relevant oviposition deterrence or attraction. The results of the present study contribute to our understanding of the effect of ageing on insecticidal solutions widely used in urban areas to control Cx. p. biotype molestus. Although an important vector of high public health importance, Cx. p. biotype molestus has been scarcely studied as target of environmentally and toxicologically reduced risk insecticides, such as spinosad.

Comparative bioassay methods to determine diamide susceptibility for two coffee pests

Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae) and Leucoptera coffeella Guérin-Méneville (Lepidoptera: Lyonetiidae) are major pests of coffee. Diamides, are a new group of insecticides that activate ryanodine receptors causing muscle contraction, and have been used to control H. hampei and L. coffeella. Bioassay methods need to be standardized for insecticide susceptibility studies on H. hampei with cyantraniliprole and L. coffeella with chlorantraniliprole. Four bioassay methods for H. hampei (topical application with a microsyringe, artificial diet, immersion of green coffee fruits in insecticide solution, and coffee branch bagging) and five for L. coffeella (spraying coffee seedlings, immersion of coffee leaves, immersion of filter paper and topical application with microsyringe were evaluated. The best performing method was selected based on the greater slope (β) of the probit curve, lower LC50, lower natural mortality in the control, and lower variance. The results showed that the best methods for bioassays were the artificial diet for H. hampei and spraying of coffee seedlings for L. coffeella.

Effects of insecticide and acaricide mixtures on Diaphorina citri control

Abstract Pesticide mixtures are commonly used to reduce production costs in agriculture. However, the consequences of such practice towards target organisms are still unknown in most cases. Therefore, this study aimed to evaluate the effects of combinations of insecticides and one worldwide used acaricide on the control of Diaphorina citri (Asian citrus psyllid). All insecticides alone (lambda-cyhalothrin+thiamethoxam, phosmet, and imidacloprid) and in combination with spirodiclofen were efficient in controlling D. citri (> 80%). No significant effects were found for combinations of lambda-cyhalothrin+thiamethoxam and phosmet insecticides with spirodiclofen. Conversely, imidacloprid caused an antagonistic effect on the control of D. citri when mixed with the acaricide. After all, spirodiclofen had no effect on the pH and electrical conductivity of insecticidal spray solutions. Spirodiclofen mixtures with lambda-cyhalothrin+thiamethoxam and phosmet had no effect on D. citri control, but combinations with imidacloprid interfered with it.

Pests of energy willow and practices to control their number

Purpose. To determine the pest species composition in bioenergy willow plantations and develop practices to control their number.Methods. Field, accounting, statistical and analytical.Results. The main pests species composition of bioenergy willow plantation in different zones have been determined, namely in the zone of sufficient moisture at the Uladivka-Liulyntsi Research Breeding Station (ULRBS), in the zone of insufficient moisture at Veselyi Podil Research Breeding Station (VPRBS) and in the zone of unstable moisture at the Bila Tserkva Research Breeding Station (BTsRBS). Of the soil pests, the most harmful for sugar beet species were found May bug, June bug and marble bug, the number of which in different areas ranged from 0.1 to 0.4 (VPRBS) to 2.0 to 4.0 (ULRBS) per 1 m2. In addition to these harmful species, there were larvae of grasshoppers and Tenebrionidae, the number of which was 0.9 to 4.0 per 1 m2, as well as larvae of cereal chafer and caterpillars of winter owl moth. The density of the soil pests population somewhat exceeded the economic thresholds of harmfulness, which should be taken into account when establishing willow plantations and during the growing season. With regard to terrestrial species, the most dangerous for willow is brown willow beetle, willow aphid and apple black miner, the number of which was also not the same everywhere. Thus, the highest population density of the brown willow beetle (beetle/10 plants) was recorded in BTsRBS (3.0 to 36.0), in ULRBS (0.5 to 3.0) and VPRBS (0.2 to 3.6). The willow aphid was found in all zones at the settlement score of 1.0 to 1.5, while apple black miner was recorded only in spring in ULRBS and BTsRBS at the settlement score of 1.0. The control of the number of phytophages in willow plantation was carried out with the aid of insecticides through pre-planting soaking cuttings and spraying planted cuttings. Soaking of cuttings in solutions of systemic action insecticides contributes to a 12.9 ̶ 22.9% increase in the plant survival compared to soaking them in water. The use of insecticides for spraying cuttings during vegetation season provides a high efficiency (76.7–100.0%) of pest control.Conclusions. Energy willow is damaged by a number of soil and terrestrial pests, namely larvae of May bug, grasshopper, Tenebrionidas, cereal chafer, Carabidae (soil pests), and brown willow beetle, willow aphid and apple bark miner (terrestrial pests). The control of the number of these phytophages is carried out mainly with the aid of insecticides through pre-planting soaking cuttings or spraying planted cuttings.

Chlorantraniliprole: A novel pesticide against lepidopteran predators of lac insect Kerria lacca (Kerr)

Crop protection plays a significant role in safeguarding productivity against insect pests. Likewise treatment of broodlac (seed material) is the starting point for achieving sustained lac production. Broodlac happen to be the major source of pest infestation on new lac crops. Laboratory and field experiments were conducted to investigate the biosafety of chlorantraniliprole against lac insect, Kerria lacca (Kerr) and find out its efficacy against key lepidopteran predators by dipping broodlac in insecticide solutions for 5, 10 and 15 min duration. Seven concentrations of chlorantraniliprole 18.5% SC formulation, ranging from 0.001% (0.05 ml L−1) to 0.0111% (0.6 ml L−1) were evaluated. Chlorantraniliprole did not show any detrimental effect on survival and settlement of 2nd instars larvae and adult female, as significant difference was not observed between treatments and control, indicating its biosafety. Treatment of broodlac with chlorantraniliprole showed pronounced effect on reduction of key lepidopteran predators viz., Eublemma amabilis (Noctuidae) and Pseudohypatopa pulverea (Blastobasidae). The treatment of rangeeni broodlac with 0.0037% concentration (0.2 ml L−1 water) for 5 min or 0.0020% (0.1 ml L−1 water) for 10–15 min duration was effective in reducing the population of E. amabilis and P. pulverea. Whereas, treatment of kusmi broodlac with 0.0056% (0.3 ml L−1 water) for 5 min dipping or with 0.0037% for 10–15 min dipping provided effective suppression of these predators. Thus treatment of broodlac prior to inoculation with chlorantraniliprole is our excellent addition to the IPM for managing the predators’ population harbored in broodlac. This study confirms the potential for use of chlorantraniliprole in lac culture for control of lepidopteran predators.

Compatibility of Steinernema carpocapsae and Heterorhabditis indica with insecticides registered against Helicoverpa armigera (Lepidoptera: Noctuidae)

The gram pod borer, Helicoverpa armigera (Lepidoptera: Noctuidae) is considered as a key pest of pigeonpea and is also a major polyphagous pest of several agricultural and horticultural crops in India. Combining chemical insecticides with Entomopathogenic Nematodes (EPNs) could be an effective alternative to reduce the use of harmful chemicals. Experiments were conducted to determine the compatibility of Steinernema carpocapsae and Heterorhabditis indica with registered insecticides used for H. armigera control in pigeon pea, under laboratory conditions. Compatibility of the insecticides with EPNs was evaluated by observing infective juveniles (IJs) survival and virulence of Galleria mellonella at 24 and 48 h after dipping in insecticide solutions. It was observed that, insecticides showed moderate effect on IJs survival. IJs were able to infect G. mellonella larvae after exposure to these chemicals, but their progeny production was significantly (P < 0.05) reduced. Both nematode species showed differential sensitivity to the tested insecticides, with H. indica exhibiting better tolerance than S. carpocapsae . The studies revealed that the chemicals showed a strong sub lethal effect on the nematode reproductive potential, limiting seriously their possible recycling in the field.

Laboratory and field trials to identify effective chemical control strategies for integrated management of Drosophila suzukii in European cherry orchards

The recent spread of the Spotted Wing Drosophila (SWD), Drosophila suzukii, in Europe has created considerable concern because of the damage recorded on various crops, in particular on sweet cherry, despite the use of conventional pesticides. Effective chemical control strategies are urgently required to improve integrated SWD management. Insecticide use should be incorporated in an IPM strategy that adopts cultural and biological control methods and tools to ensure high protection of cherry production while fulfilling export market requirements. Laboratory and field trials were conducted in North-Eastern Italy to identify the most effective and sustainable insecticides to be used against SWD in cherry orchards. In the laboratory, cherries previously infested by SWD were dipped in insecticide solutions to assess their effectiveness in controlling eggs and larvae. In other laboratory trials cherries were first treated with insecticides and then exposed to adults to assess residual activity. A number of chemical control strategies (including one designed for organic orchards) were then compared in cherry orchards. These strategies were planned also considering the need to control the European cherry fruit fly Rhagoletis cerasi L., a key pest of cherry in Europe and elsewhere. A number of formulations based on cyantraniliprole, spinosad, spinetoram, phosmet, lambda-cyhalothrin and deltamethrin were effective against different life stages of SWD in the laboratory. SWD control in the field was influenced by the use of above-mentioned insecticides and the number of applications during the cherry ripening period. Insecticides selected for the protection of organic cherry orchards were almost ineffective. Some strategies defined for conventional orchards were also effective against R. cerasi. In most cases (dimethoate was the exception) insecticide residues were lower than maximum residue limits required by the European Union to export cherries to major markets. In conditions of high pest pressure, three to four applications with active ingredients having different modes of action were needed to keep D. suzukii and R. cerasi damage beneath economic thresholds. Sanitation and harvest management could be helpful in lowering pesticide use. A number of tactics such as insect-proof nets, biological and cultural methods should be incorporated for an effective IPM strategy with benefits not only for human and environmental health but also in terms of the lifetime of currently effective insecticides.

Resistensi populasai hama bawang merah Spodoptera exigua (Lepidoptera: Noctuidae) terhadap klorfluazuron

Resistance of Onion Pest Spodoptera exigua (Lepidoptera: Noctuidae) Populations to Chlorfluazuron. The research was conducted from August 2001 until April 2002 in the Kalitiro Agriculture Training and Development Research Station, Gadjah Mada University. The objective of research was to determine the resistance level of Spodoptera exigua populations collected from the district of Sanden, Kretek, Wates, Temon, Panjatan, Wonosari, Panggang and Playen (all are in Yogyakarta Province) to chlorfluazuron insecticide. Research was conducted by dipping artificial diet about 30 seconds in insecticide solution and there are used test two hours after they were air dried. Based on the preliminary test, different concentrations were tested to determine the toxicity of the insecticide to each population. Third instar larvae (five days old) of the first generation were used in bioassays. Each larvae with its artificial diet was placed in a plastic cup (diameter 3,5 cm). Larval mortality was recorded at 72 hours after exposure. Data was analyzed using probit analysis to determine LC50 values. The result showed that the LC50 values of chlorfluazuron againsts eight population of S. exigua at 72 hours after exposure varied from 16,10 ppm (Panggang) to 84,76 ppm (Panjatan). The results suggested that all populations from Panggang, Playen, Kretek, Sanden, Wates, Wonosari and Temon were still susceptible to chlorfluazuron. Population from Panjatan indicated to be resistant to chlorfluazuron.