Number Of Insecticide Applications Research Articles

Effects of the area of source habitat and habitat connectivity on soybean pod borer damage: Implications for area-wide management

The soybean pod borer, Leguminivora glycinivorella (Matsumura), is an important soybean pest that reduces both quality and yield in Asia, and chemical control is used irrespective of the damage risk. The pest population density increases at continuously cropped soybean fields (hereafter, source habitat). The present study would contribute to proposing pest management options matched to the damage risk by clarifying the surrounding landscape structures where damage is likely to increase. First, we clarified the relationship between the probability of grain damage and the source habitat within a 350 m radius of the new or continuously cropped soybean fields. The habitat area surrounding continuous soybean fields positively influenced the probability of grain damage but did not detect a significant effect in new soybean fields. Secondly, we clarified the relationship between the probability of grain damage and habitat connectivity in continuous soybean fields. Well-managed fields with high connectivity consistently showed low damage risk. Meanwhile, damage risk varied in fields with low connectivity, indicating that damage is unlikely to occur because soybean pod borers are difficult to invade. However, once invaded, the damage could be extensive. Considering these results, one possible new control system will allow the spatiotemporal variation in the number of insecticide applications. The present study likely contributes to understanding the relationship between soybean pod borer injury and landscape structure, which is important for area-wide pest management.

IPM IN SOYBEANS: HOW TO REDUCE CROP DAMAGE AND INCREASE PROFIT FOR THE FARMER

The objective of the present work was to implement integrated pest management (IPM) in the soybean crop, comparing it with the management carried out by the farmer during two consecutive seasons. The monitoring of adult lepidopterans was also evaluated using Delta-type traps baited with the sexual pheromones of Spodoptera frugiperda (Bio Spodotera®), Helicoverpa armigera (Bio Helicoverpa®) and Chrysodeixis includens (Bio Pseudoplusia®). Incidence of caterpillars and stinkbugs in soybeans was weekly determined, both in the IPM area and in the farmer, area using the beat cloth method. Insecticide applications in the IPM area were carried out when pest population densities reached the control level, while in the area managed by the farmer, sprayings were carried out at his discretion. Based on the results obtained, we found that adoption of IPM enabled better control of the pests in soybeans, especially for stink bugs, and the number of insecticide applications in soybeans could be reduced, which provides economic and environmental benefits for the farmer. In addition, we found that the sexual pheromones of the three evaluated pest species are effective in capturing their moths.

Patterns of Insecticide Use and Farmers' Knowledge Level in Managing <i>Leucinodes orbonalis</i> Guenee in Tamil Nadu

A study was conducted to record the pattern of insecticide usage and knowledge level of farmers in handling insecticides to control shoot and fruit borer Leucinodes orbonalis Guenee from major brinjal growing districts of Tamil Nadu during 2022 -2023. This study found that, 22 different insecticides were imposed for the management of Leucinodes orbonalis and among them chlorantraniliprole 18.5% SC (83.00%) was recorded as the highest usage insecticide followed by spinetoram 11.7% SC (72.00%). The number of insecticide applications among various districts varied from 9.9 to 24.7 per cropping season at an interval ranging 4.9 to 12.3 days. The major source of information regarding pesticides to the farmers were pesticide dealers (65.00%) and about 98.00% of the farmers did not pay attention towards label on pesticide containers. Only around 40.00% of farmers followed recommended dose and nearly 60.00% did not follow any safety measures while spraying. Study inferred that, more than 84.00% brinjal growing farmers completely relay on pesticides for the management of Leucinodes orbonalis in brinjal.

Contrasting effects of wooded and herbaceous semi-natural habitats on supporting wild bee diversity

The use of pesticides and the lack of resources caused by the simplification of landscapes are often cited as the main drivers of the loss of wild bees. Landscape complexity has been shown to interact with local pesticide use in studies of the effect of these factors on the abundance and diversity of insects. But, to date, few studies have simultaneously investigated local and landscape effects on wild bees using more precise descriptors of the landscape and of farming practices. The aim of the present study was thus to disentangle the effects of landscape composition and farming practices on the taxonomic and functional diversity of wild bees and their possible consequences for pollination potential. We analysed a dataset of 107 crops at whose edges wild bees were captured between 2013 and 2019. Pesticide treatments of each crop were recorded throughout the year. At the landscape level, the proportions of different types of land use were calculated in a circle with a radius of 500 m. We caught 1536 wild bees belonging to 86 species and, using generalized mixed modelling, found that the number of insecticide applications had a negative effect on wild bee abundance and richness, while forest cover within a 500-m radius had a positive effect on wild bees whatever the farming practices. However, we also showed that the effect of the proportion of permanent grasslands on taxonomic and functional diversity of wild bees differed depending on the use of fungicides in the field. Finally, we found a negative effect of the number of herbicide applications on pollination potential. This study advances our understanding of the contrasting but complementary roles of diverse semi-natural habitats in agricultural landscapes in supporting wild bee diversity and which, under certain conditions, may buffer the detrimental consequences of pesticide use.

Dynamic Economic Thresholds for Insecticide Applications Against Agricultural Pests: Importance of Pest and Natural Enemy Migration.

In Integrated Pest Management programs, insecticides are applied to agricultural crops when pest densities exceed a predetermined economic threshold. Under conditions of high natural enemy density, however, the economic threshold can be increased, allowing for fewer insecticide applications. These adjustments, called 'dynamic thresholds', allow farmers to exploit existing biological control interactions without economic loss. Further, the ability of natural enemies to disperse from, and subsequently immigrate into, insecticide-sprayed areas can affect their biological control potential. We develop a theoretical approach to incorporate both pest and natural enemy movement across field borders into dynamic thresholds and explore how these affect insecticide applications and farmer incomes. Our model follows a pest and its specialist natural enemy over one growing season. An insecticide that targets the pest also induces mortality of the natural enemy, both via direct toxicity and reduced resource pest densities. Pest and natural enemy populations recover after spraying through within-field reproduction and by immigration from neighboring unsprayed areas. The number of insecticide applications and per-season farmer revenues are calculated for economic thresholds that are either fixed (ignoring natural enemy densities) or dynamic (incorporating them). The model predicts that using dynamic thresholds always leads to reduced insecticide application. The benefit of dynamic thresholds in reducing insecticide use is highest when natural enemies rapidly recolonize sprayed areas, and when insecticide efficacy is low. We discuss real-life situations in which monitoring of natural enemies would substantially reduce insecticide use and other scenarios where the presence of beneficial organisms may lead to threshold modifications.

Insecticides in Use and Risk of Control Failure of Boll Weevil (Coleoptera: Curculionidae) in the Brazilian Cerrado.

Growers rely on synthetic insecticides to control the boll weevil throughout the reproductive cotton stage. An average of 19.6 insecticide applications (range: 10 to 30) for control of boll weevil were found in a survey with growers in the Brazilian Cerrado, covering an area of 494,100 hectares of cotton. Twenty-one insecticides were applied, with 64.8% of the applications made with malathion, fipronil, carbosulfan, and thiamethoxam + lambda-cyhalothrin. These four insecticides were used by 100, 76, 70, and 62% of the growers, with respectively 7.2, 2.1, 1.8, and 1.6 applications. Growers classified their boll weevil control achieved into four categories (fair, good, very good, or excellent), without correlation between these categories with the number of insecticide applications. Control of cotton regrowth and volunteer cotton plants were the major obstacles for effective boll weevil management, followed by the low efficacy of insecticides. Five registered insecticides to spray cotton against other pests than boll weevil were enlisted by growers with potential for recommendation. A boll weevil standard population for susceptibility was assayed with 27 insecticides and the results presented within a failure risk quotient (FRQ). The FRQ of eight, six, and 13 of the 27 tested insecticides was high, intermediate, and low, respectively. The high FRQ included 7 of 10 pyrethroid formulations, pymetrozine, and methomyl. On the opposite end, fipronil had the lowest FRQ value.

Bio-efficacy of Belt Expert 480 SC against caterpillars and sucking pest complex in black gram (Vigna mungo L. Hepper) and its effect on natural enemies and plants

The use of insecticides as a combination product with different modes of action and target may help in the reduction enhancement of categories of pests. Furthermore, the number of insecticide applications would be reduced which may pave the opportunity for an easy fit into the strategies of integrated pest management. Therefore, the field experiments were carried out at the Main Agricultural Research Station, Dharwad, Karnataka, India for two consecutive kharif seasons to evaluate bio-efficacy of combination product Belt Expert 480 SC (Flubendiamide 24% + Thiacloprid 24% SC w/v) against caterpillars and sucking pest complex in black gram and their safety towards non-target organisms. Field trials consisted of nine treatments replicated three times in a randomized block design. Results revealed that two sprays of the combi-product Belt Expert 480 SC (Flubendiamide 24% w/v + Thiacloprid 24% w/v SC) @ 250 mL/ha recorded lower pod borer incidence (4.54%) with higher seed yield (9.13 q/ha) followed by Belt Expert 480 SC (Flubendiamide 24% w/v + Thiacloprid 24% w/v SC) @ 200 mL/ha with pod borer incidence of 5.47% and seed yield of 8.83 q/ha. The treatments viz., Belt Expert 480 SC (Flubendiamide 24% w/v + Thiacloprid 24% w/v SC) @ 200 and 150 mL/ha, Alanto 240 SC (Thiacloprid 21.7% w/w SC) @ 250 mL/ha and Fame 480 SC (Flubendiamide 39.35% m/m SC) @ 100 and 125 mL/ha proved safe to natural enemies. None of the insecticidal treatments (Belt Expert 480 SC (Flubendiamide 24% w/v + Thiacloprid 24% w/v SC) @ 250, 500 and 1000 mL/ha) showed any type of phytotoxic symptoms on black gram plants.

Farmers’ Preferences for Cotton Cultivation Characteristics: A Discrete Choice Experiment in Burkina Faso

While a fierce debate about the advantages and disadvantages of genetically modified crops is ongoing, it is surprising that farmers are often not consulted. In Burkina Faso, where insect resistant Bollgard II® cotton (further termed Bt cotton) was commercially released in 2008, studies highlight that cotton producers are in general satisfied with the reduction in insecticide use while the economic benefits are a source of controversy. To gain insight into farmers’ preferences towards attributes in cotton cultivation, a discrete choice experiment (DCE) was developed. Five key attributes were identified to describe improved cotton varieties: seed development and provenance, seed costs, yield, required number of insecticide sprays, and preservation of agricultural practices. Farm-gate surveys were conducted among 324 cotton farmers in Western Burkina Faso. The results show that overall, farmers have a positive preference towards yield improvements and a negative preference towards pure private seed development and towards an increase in the requested number of insecticide applications or in the seed costs. According to their varieties at the time of the surveys (Bt and non-Bt), a difference was observed regarding their preferences for a status quo situation, indicating that those growing Bt had a stronger preference to keep the status quo than non-Bt farmers. When dividing the sample in segments based on the farm size, it was shown that there were different preferences with respect to the development of the variety and the required number of insecticide applications. Overall, it can be concluded from this study that economic benefits (linked to higher yields, lower seed costs, or reduced pesticide use) shape farmer’s preferences.

Evaluation of non‐target effects of OMRI‐listed insecticides for management of Drosophila suzukii Matsumura in berry crops

AbstractThe spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive pest of many fruit crops throughout North America, South America and Europe. The presence of this destructive pest has led to an increase in the number of insecticide applications. While conventional growers have an arsenal of different insecticides at their disposal, organic growers have a limited selection of effective options and rely heavily on applications of Entrust®, the organic formulation of spinosad. An important part of research is to develop more tools for organic growers and evaluate the effects of insecticides intended to target D. suzukii on natural enemies in the system. The effects of six organic pesticides alone and in combination with three adjuvants and two phagostimulants were tested in laboratory bioassays on three common natural enemies in berry production systems including two predators, Chrysoperla rufilabris and Orius insidiosus, and a parasitoid wasp, Aphidius colemani. Under the IOBC toxicity rating scale, spinosad was rated consistently from slightly harmful to harmful across natural enemy species and residue age (the effects of pesticides over time). Sabadilla alkaloids caused mortality to O. insidiosus equal to that of spinosad. All tested pesticides were at least slightly harmful to A. colemani, and the adjuvant polyether‐polymethylsiloxane‐copolymer polyether caused mortality that was not significantly different from spinosad. In general, neither the addition of adjuvants nor phagostimulants increased the mortality of the insecticides tested. The exception was polyether‐polymethylsiloxane‐copolymer polyether, but it is unclear whether it increased the toxicity of the pesticides or was simply toxic itself since it caused high mortality to A. colemani when applied alone. Sublethal effects were measured for two predatory species by measuring eggs laid and % egg hatch. Minimal sublethal effects were observed in C. rufilabris. In contrast, all tested insecticides caused reduced egg hatch in O. insidiosus compared with the control.

Susceptibility of Brown Planthopper (Nilaparvata lugens Stal.) from Cipunagara and Banyuwangi Population to Neem Oil Formulation

Brown Planthopper is one of the pests that cause problems in rice production. This study was conducted to know the tendency of using a kind of insecticide and to examined the susceptibility of brown planthopper from field population (Cipunagara, West Java) compared to standard population (Banyuwangi, East Java) to formulation insecticide of neem oil 50 EC. Observations wereconducted on Cipunagara farmers to find out the kind of insecticide used and the number of insecticide applications in one season. the susceptibility test to neem oil 50 EC formulation was conducted by root dipping method. Brown planthopper was feed on treated plant for two days and then the next day the Brown Planthopper was fed on rice plant without treatment until the eighth day. Test insects used are brown planthopper instar 4 th . Observations of insect mortality test for ten days with an interval of every 24-hour observation. Susceptibility values for neem oil insecticide formulations were determined based on the resistance ratio (RR) by comparing the LC 50 value of the field population and standard population. Result of the observations showed that the farmers in the Padamulya village, Cipunagara district generally using synthetic insecticides to control of this pest. The active ingredient of most mentioned was imidacloprid with a lot of different applications. The result of examination of insecticide formulation of neem oil 50 EC using the root dipping method showed that a slow death trend and the highest mortality at eight days after application. The LC 50 value of neem oil 50 EC insecticide against brown planthopper in the field population (Cipunagara) was 0.36% and RR 0.98. The result indicated that brown planthopper origin from Cipunagara was still susceptible to neem oil 50 EC insecticide formulation. Keyword: Neem oil formulation, Susceptilbility, Resistance ratio, Brown Planthopper

Susceptibility of Brown Planthopper (Nilaparvata lugens Stal.) from Cipunagara and Banyuwangi Population to Neem Oil Formulation

Brown Planthopper is one of the pests that cause problems in rice production. This study was conducted to know the tendency of using a kind of insecticide and to examined the susceptibility of brown planthopper from field population (Cipunagara, West Java) compared to standard population (Banyuwangi, East Java) to formulation insecticide of neem oil 50 EC. Observations wereconducted on Cipunagara farmers to find out the kind of insecticide used and the number of insecticide applications in one season. the susceptibility test to neem oil 50 EC formulation was conducted by root dipping method. Brown planthopper was feed on treated plant for two days and then the next day the Brown Planthopper was fed on rice plant without treatment until the eighth day. Test insects used are brown planthopper instar 4 th . Observations of insect mortality test for ten days with an interval of every 24-hour observation. Susceptibility values for neem oil insecticide formulations were determined based on the resistance ratio (RR) by comparing the LC 50 value of the field population and standard population. Result of the observations showed that the farmers in the Padamulya village, Cipunagara district generally using synthetic insecticides to control of this pest. The active ingredient of most mentioned was imidacloprid with a lot of different applications. The result of examination of insecticide formulation of neem oil 50 EC using the root dipping method showed that a slow death trend and the highest mortality at eight days after application. The LC 50 value of neem oil 50 EC insecticide against brown planthopper in the field population (Cipunagara) was 0.36% and RR 0.98. The result indicated that brown planthopper origin from Cipunagara was still susceptible to neem oil 50 EC insecticide formulation. Keyword: Neem oil formulation, Susceptilbility, Resistance ratio, Brown Planthopper

Integrated pest management approaches against Drosophila suzukii

The appearance of Drosophila suzukii in 2009 has strongly affected the cherry cultivation. Prior to SWD invasion, Italian cherry orchards were treated with only two insecticide applications, the first against aphids (Myzus cerasi Sulz.) before flowering and the second against Rhagoletis cerasi, about 20-30 days before harvest. After D. suzukii invasion, additional two-three pre-harvest (close to harvest) insecticide treatments are required, but the number of insecticide applications can increase to 5-8 depending on pest abundance, crop susceptibility and other environmental factors. The intensive use of insecticides poses serious concerns about the presence of residues on fruits exceeding maximum residue limits (MRLs), the development of resistance, and negative impacts on the environment beyond beneficials. To obtain a good and sustainable control of D. suzukii the chemical strategies should be coupled with cultural management the use of nets and parasitoids. To achieve good control of the carpophagus it is essential to monitor, as well as the adults with trap lured with blends of fermentig substances, the oviposition on the ripening fruit, because the percentage of infestation is not related to the number of catches in the food traps. Considering the viability of SWD eggs and larvae is lower under dry, warm conditions, cool humid microhabitats should be avoided by pruning to open up the canopy in order to increase airflow on the trees and reduce shading. In addition, the use of mulches reducing standing water can further contribute to the reduction of humidity in fruit orchards. Precision irrigation should also be incorporated to reduce pooling of water on the ground. Mass trapping, placing numerous traps around the perimeter outside fruit fields, is suitable and cost-effective method only for cultivations where the pest pressure is considerably low, if necessary insecticides could be applied to the surface of the traps to function as an attract-and-kill strategy. Among the sustainable protection techniques for the control of D. suzukii, the use of insect-proof nets has proved effective, reducing or completely replacing the use of insecticides in some instances, and providing high levels of exclusion of D. suzukii from the crop. During the ripening season, sanitary measures such as removal of dropped, infested and over-ripe fruits is suggested. The collection and treatment of infested fruit through sun exposure, disposal in closed containers, crushing, low temperature treatments, bagging and burying, to destroy D. suzukii eggs and larvae are Fig. 6 - Tecniche di produzione integrata per il contenimento di Drosophila suzukii Fig. 6 - Integrated production techniques for Drosophila suzukii control Integrated pest management against D. suzukii 73 essential IPM procedures to limit the infestation of healthy fruit. The augmentative release of parasitoids and conservation biocontrol of generalist predators, potentially, could contribute to the integrated management of D. suzukii populations, especially in natural habitats close to commercial crops, however further work on the effectiveness of native parasitoids and generalist predators in Europe and the USA, in the field, is required. In this paper, the integration of different tools for D. suzukii control will be discussed, in order to develop effective, eco-friendly and practical strategies in the management of the pest on cherry

The impact of the EU neonicotinoid seed-dressing ban on oilseed rape production in England.

Neonicotinoid seed dressings on oilseed rape were banned in the European Union (EU) from December 2013. A survey of > 200 farms was conducted in England in the 2014/15 and 2015/16 seasons to assess the impact of the ban on changes in crop area, crop losses to cabbage stem flea beetle (CSFB), insecticide use and the economics of oilseed rape production. The area of oilseed rape grown fell in both seasons, with CSFB identified as the third most important reason for the decrease. Crop losses to CSFB were 3% and 5% in the respective seasons, with clear variation by county. There were clear differences in the crop area treated (1.14 vs 0.77 million ha) and the number of insecticide applications per crop (2.0 vs 1.4) to combat CSFB in 2014/15 and 2015/16, respectively. Within the derogation area counties there was a clear reduction in the number of applications per crop when neonicotinoid-treated vs non-treated seed was used (1.0 vs 1.9), respectively. Increasing resistance to pyrethroid insecticides in combination with the neonicotinoid seed dressing ban is likely to have significant impacts on the viability of growing oilseed rape in England particularly where CSFB activity/risk is high. © 2018 Society of Chemical Industry.

Dominance of cropland reduces the pollen deposition from bumble bees

Intensive agricultural landscapes can be hostile for bees due to a lack of floral and nesting resources, and due to management-related stress such as pesticide use and soil tillage. This threatens the pollination services that bees deliver to insect-pollinated crops. We studied the effects of farming intensity (organic vs. conventional, number of insecticide applications) and availability of semi-natural habitats at the field and landscape scale on pollinator visits and pollen delivery to pumpkin in Germany. We found that wild bumble bees were the key pollinators of pumpkin in terms of pollen delivery, despite fivefold higher visitation frequency of honey bees. Critically, we observed that the area of cropland had stronger effects on bees’ pollen deposition than the area of seminatural habitats. Specifically, a 10% increase of the proportion of cropland reduced pollen delivery by 7%. Pumpkin provides a striking example for a key role of wild pollinators in crop pollination even at high numerical dominance of honey bees. In addition, our findings suggest that habitat conversion to agricultural land is a driver of deteriorating pollination. This underlines the importance to maintain sufficient areas of non-crop habitats in agricultural landscapes.

Evaluating integrated pest management tactics for onion thrips and pathogens they transmit to onion

Onion thrips (Thrips tabaci) is a significant pest of onion worldwide, causing both direct and indirect damage to the crop. Integrated pest management of onion thrips should improve profitability and sustainability of onion production. Promising management approaches include reducing nitrogen application rates, using thrips-resistant cultivars and implementing action threshold-based insecticide programs. However, the impact of these integrated pest management approaches on thrips densities and damage, crop yield, and thrips-associated plant diseases like iris yellow spot (IYS) (caused by Iris yellow spot virus) and bacterial center rot (caused by Pantoea agglomerans and P. ananatis) remains largely unknown. In a two-year field trial in New York, combinations of varying levels of nitrogen applied at planting (67, 101 and 140kgha−1) and different insecticide programs (standard weekly insecticide program and action threshold-based insecticide program) were evaluated for onion thrips management in onion cultivars that had moderate resistance (‘Avalon’), low resistance (‘Delgado’) and no resistance (‘Bradley’) to onion thrips. Results indicated that regardless of cultivar, nitrogen did not affect larval thrips densities, onion yields, IYS or bacterial center rot. Across all cultivars, insecticide use (both programs) significantly reduced larval thrips densities and damage, IYS severity and incidence, and increased onion yield. Insecticide use did not consistently affect the incidence of bacterial center rot. Both insecticide programs reduced onion thrips larval densities by 60–81% relative to the untreated control, but the action threshold-based application program used 2.8 fewer applications than the standard program. ‘Avalon’ had low thrips densities and IYS disease, but required the same number of insecticide applications as ‘Bradley’. Onion yields in both insecticide programs were statistically similar in both years, and bulb weights averaged 10–54% more than those in the untreated control. Our results indicated that growers can reduce nitrogen levels at planting and insecticide use without compromising control of either onion thrips or IYS disease or onion bulb yields.

Spatial and temporal incidence of insect pests in farmers’ cabbage fields in Senegal

Abstract In Senegal, damage caused by insect pests is a major obstacle to seasonal stability and an increase in cabbage production. Little is known about the spatial and temporal distribution of cabbage pests, which makes the design of management recommendations to small-scale farmers challenging. The objectives of this study were to: (i) evaluate the status of insect pests observed in cabbage farmers’ fields; (ii) give information on the spatial and temporal distribution of key pests and (iii) assess the effect of temperature, insecticide applications, and host crop abundance on their incidence. A total of 116 cabbage fields were monitored for insect pests and related damage over four crop cycles, from October 2012 to May 2014, in the main vegetable producing area of Senegal (Niayes). The diamondback moth Plutella xylostella (L.) was by far the most important pest present in all the fields and with high levels of incidence (37.1% infested plants), particularly in the latter part of the dry season in the South of Niayes (50% infested plants). The cabbage webworm Hellula undalis (F.) was mainly observed in the early dry season in the south of Niayes, with an incidence of up to 12.5% infested plants. More surprising was the detection of the tomato fruit worm Helicoverpa armigera (Hübner), with damage of up to 9.4% of cabbage heads. The incidence of sucking pests such as whiteflies Bemisia tabaci (Gennadius), or aphids (including Lipaphis pseudobrassicae (Davis, 1914), Myzus persicae (Sulzer) or Brevicoryne brassicae (L.)) was generally low. The incidence of P. xylostella increased significantly with the number of insecticide applications, indicating that control deployed by growers was ineffective. The incidence of H. undalis did not depend on the number of insecticide applications, but significantly increased with host crop abundance and decreased with temperature. This study is a first step towards developing alternative pest management strategies in the framework of sustainable vegetable production systems.

Parasitoid control of the tomato fruitworm, Helicoverpa armigera, in smallholder farmer fields in Senegal

ABSTRACTIn Africa, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) is a key pest of cotton and vegetable crops, particularly tomato. Alternatives to insecticides to control this pest are needed such as conservation biological control. However, knowledge on the diversity and ecology of naturally occurring enemies of H. armigera is limited. A two-year field survey was conducted in a set of tomato farmer fields in the main vegetable-growing area in Senegal (Niayes) to assess the spatial and seasonal occurrence of indigenous parasitoids of H. armigera, and to evaluate the effect of insecticide use on biological control efficiency. No parasitoid emerged from H. armigera eggs. Incidence of larval parasitoids was generally moderate (20%) but highly variable (0%–100%) among fields, independently of host abundance, and negatively affected by the number of insecticide applications. Larval parasitism was largely dominated by the larval parasitoid Meteorus laphygmarum Brues (Hymenoptera, Braconidae), but a positive correlation was found between specific richness or Shannon diversity index of the parasitoid community and parasitism rate. This study is a first step toward development of research and extension programs for conservation of natural enemies in the framework of integrated management of the tomato fruitworm in Senegal.

Estimating the development rate of the tomato leaf miner, Tuta absoluta (Lepidoptera: Gelechiidae), using linear and non-linear models.

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is native to South America and has recently invaded European, African and Asian countries, where it is causing severe damage to tomato crops leading to an increase in the number of insecticide applications. This situation has prompted a demand for alternative pest management strategies aiming to control T. absoluta and concomitantly reduce insecticide applications. The development period for immature stages of T. absoluta at constant temperatures was modelled to select appropriate mathematical functions for simulating its development. The performance of the models varied according to the insect development stage, but in general all models performed well considering the statistical criteria used. Discrimination among models was possible only when the reliability of the temperature thresholds estimated by the models was used as an additional criterion. In this case, the models Briere-1, Lactin-2 and Shi proved adequate to describe the relationship between temperature and development rate of T. absoluta. These models provide an important tool to predict the occurrence of the immature stages of T. absoluta in the field in order to determine the best period for implementing control measures. This is an important contribution to the development of pest management strategies for T. absoluta. © 2016 Society of Chemical Industry.

Management strategies in apple orchards influence earwig community

Our aim was to assess whether different apple orchard management strategies (low-input, organic, Integrated Pest Management (IPM)) would have an effect on earwigs, which are important natural enemies of apple pests. These commercial orchards were as well compared to abandoned orchards. The density of Forficula auricularia and Forficula pubescens was studied for three years in 74 orchards around Avignon. The pesticide usage, some orchard characteristics and two small-scale landscape parameters were characterized. Pesticide use was significantly different between low-input, organic and IPM orchards with particularly significant differences in the number of insecticide applications (2.2, 4.9 and 9.2 respectively). Pesticide use had a much stronger impact on earwig community than other characteristics. F. auricularia density was significantly lower in IPM orchards (0.47 individuals per tree) compared to organic, low-input and abandoned orchards (3.1, 4.5 and 1.6 individuals per tree, respectively). F. pubescens was almost absent from IPM orchards and its abundance was higher in abandoned or low-input orchards compared to organic orchards (1.5 and 2.8 vs 0.8 individuals per tree). The percentage of F. pubescens in the earwig community decreased from abandoned (52%) to low-input (40%), organic (15%) and IPM orchards (0.5%). These results were confirmed by LD50 assays showing that for the two pesticides causing mortality close to normal application rates (chlorpyrifos-ethyl and acetamiprid), F. pubescens was significantly more sensitive than F. auricularia. Since earwigs are also easy to capture and identify, they may be useful to estimate the effects of management strategies and their modification in pome fruit orchards.

Integrated control of two tortricid (Lepidoptera) pests in apple orchards with sex pheromones and insecticides

The apple is attacked by a significant number of insect pests in Brazilian commercial orchards, including Bonagota salubricola and Grapholita molesta (Lepidoptera: Tortricidae). Sexual disruption of B. salubricola and G. molesta was evaluated in apple orchard using the flowable pheromone formulations, SPLAT Grafo+Bona (SG+B), SPLAT Attract and Kill Grafo+Bona (SAKG+B), and compared with the standard insecticides used for management in the Integrated Apple Production (IAP) system. Both formulations were applied at a rate of 1kg/ha on October 10, 2005 and December 13, 2005 using 300 and 1000 point sources/ha of SG+B and SAKG+B, respectively in experimental units of 7 ha. Adult male captures of B. salubricola and G. molesta were evaluated weekly in Delta traps with specific synthetic sex pheromone from October 10, 2005 to February 14, 2006. Damage to fruits was evaluated on November 21 and December 21, 2005, and January 25 and February 14, 2006. In the SPLAT treated experimental units a significant reduction was observed in the number of B. salubricola and G. molesta males caught in Delta traps compared to the experimental unit IAP. Damage by B. salubricola at harvest ranged from 1.63 to 4.75% with no differences between treatments, while damage by G. molesta was near zero in all experimental units. Mating disruption using SG+B and SAKG+B was sufficient to control B. salubricola and G. molesta with results equivalent to IAP guidelines. This technology is promising for management of both pests in Brazilian apple orchards with immediate reduction of 43% in the number of insecticide applications.