The wheat aphid Sitobion miscanthi (CWA) is an important harmful pest in wheat fields. Insecticide application is the main method to effectively control wheat aphids. However, CWA has developed resistance to some insecticides due to its extensive application, and understanding resistance mechanisms is crucial for the management of CWA. In our study, a new P450 gene, CYP4CJ6, was identified from CWA and showed a positive response to imidacloprid and thiamethoxam. Transcription of CYP4CJ6 was significantly induced by both imidacloprid and thiamethoxam, and overexpression of CYP4CJ6 in the imidacloprid-resistant strain was also observed. The sensitivity of CWA to these two insecticides was increased after the knockdown of CYP4CJ6. These results indicated that CYP4CJ6 could be associated with CWA resistance to imidacloprid and thiamethoxam. Subsequently, the posttranscriptional regulatory mechanism was assessed, and miR-316 was confirmed to participate in the posttranscriptional regulation of CYP4CJ6. These results are crucial for clarifying the roles of P450 in the resistance of CWA to insecticides.

Cotton crops are an important agricultural product in Egypt. However, the bollworm Earias insulana is a significant pest of cotton. Field experiment was carried out during the 2018 and 2019 seasons at Qaha Experimental Station, Qalyoubia governorate to determine the best dates for sowing cotton crops, to minimize E. insulana infestation and maintain high populations of the predators of spiny bollworm. The latest sowing date had a significantly lower infestation of squares, flowers and green bolls than the other two sowing dates. After spraying the three planting date plots with profenofos, lambda-cyhalothrin and methomyl insecticides, infestation of cotton bolls by spiny bollworm was significantly reduced in treated compared with untreated plots. A significant positive correlation (r = 0.829* and 0.827*) was found between the average temperature and E. insulana infestation of squares and flowers, respectively, for the first planting date and (r = 0.819*) in squares for the second planting date of untreated plots of season 2018. The explained variance percentages of multiple regression analysis showed that the effects of mean temperature and relative humidity (RH) on the third sowing date had a significantly lower infestation of squares, flowers and green bolls by spiny bollworm as compared to the first and second sowing dates. The populations of common natural enemies of E. insulana on cotton plants, i.e., Chrysoperla carnea, Coccinella undecimpunctata and spiders were counted during the two seasons. The correlation between the RH percentage and populations of the three predators was insignificantly positive during the 2018 season, while it was negatively or positively insignificant during the 2019 season. The correlation between the mean temperature and the populations of the three predators was insignificantly negative for C. carnea and positive for spiders during the 2018 season, whereas a positive correlation was found between temperature and C. carnea and spiders and a negative correlation between temperature and C. undecimpunctata during the 2019 season.

Field experiments were conducted to determine the effects of tank-mix and sequential postemergence (POE) applications of the insecticides carbaryl and dimethoate with sethoxydim on large crabgrass control and cotton tolerance. Large crabgrass control was similar with sethoxydim and sethoxydim-dimethoate tank mixtures. Although tank mixing carbaryl with sethoxydim reduced control, it was not reduced when carbaryl was applied 2 days before or 2 days after applying sethoxydim. Neither the insecticides nor sethoxydim applied alone or as tank mixtures injured cotton or affected lint yield, percent lint, fiber length, fiber length uniformity, fiber strength, or micronaire.

Annual losses of cocoa in Ghana from mirids are significant; therefore, accurate timing of insecticide application is critical to enhance yields. However, cocoa farmers often lack information on the expected mirid population for each season to enable them to optimize pesticide use. This study assessed farmers' knowledge and perceptions of mirid control and their willingness to use forecasting systems informing them of the expected mirid peaks and the time of pesticide application. A total of 280 farmers were interviewed in the Eastern and Ashanti regions of Ghana with a structured open- and closed-ended questionnaire. Most farmers (87%) considered mirids the most important insect pest on cocoa, with 47% of them attributing 30–40% of annual crop losses to mirid damage. There was a wide variation in the timing of insecticide application as a result of farmers using different sources of information to guide the start of application. The majority of farmers (56%) did not have access to information about the type, frequency and timing of insecticide use. However, respondents who were members of farmer groups had better access to such information. Extension officers were the preferred channel for information transfer to farmers, with 72% of farmers preferring them to other available methods of communication. Almost all the respondents (99%) saw the need for a comprehensive forecasting system to help farmers manage cocoa mirids. The importance of the accurate timing of mirid control based on forecasted information to farmer groups and extension officers is discussed.

Glutathione S-transferases (GSTs) have been recognized as important metabolic detoxifying enzymes in many phytophagous insects. However, the contribution of GST to insecticide resistance in Zonocerus variegatus (L.) has not been studied. Therefore, we carried out an initial study on the induction and kinetics of GST in Z. variegatus exposed to pyrethroids (PYRs) and Ocimum gratissimum leaf extract. Fifth-instar nymphs of Z. variegatus collected from cassava farms (with no history of insecticide exposure) on the campus of the University of Ibadan were reared to adult stage. Adult insects were divided into four groups of two replicates, each consisting of 30 insects. The groups were exposed to 20 ml of PYR insecticide and 25 mg/dl and 250 mg/dl of O. gratissimum leaf extract, respectively, while the last group served as the control. GST was extracted from the body tissues of the insects using the Bradford method and the kinetics of the enzyme was evaluated using the Lineweaver–Burk plots. No mortality was recorded in insects exposed to 25 mg/dl of O. gratissimum leaf extract, while mortality rates of 93.3 and 43.3% were recorded in insects exposed to PYR insecticide and 250 mg/dl of O. gratissimum leaf extract, respectively. The activity of GST was higher in insects exposed to the insecticides than in the control insects, while a higher enzyme activity was recorded in insects that died after exposure to the insecticides than in insects that were alive after exposure. The GST extracted from insects that were alive after exposure to PYR insecticide and O. gratissimum leaf extract exhibited a high affinity for the glutathione substrate compared with that extracted from insects that died after exposure. Higher GST activity in insects exposed to insecticides is indicative of the role of this enzyme in the metabolic detoxification of insecticides by Z. variegatus.

Introduction. Plants develop mechanisms that allow them to compartmentalize injuries that they suffer during their life. In trees, pruning and injection treatments must be used in accordance with precise rules to reduce risks resulting from the injuries created. Sealing in palms. Palms, contrary to widespread belief, are quite capable of “healing” injuries (sealing); because of an anatomy quite different from trees, the sealing process in palms is much simpler. Compartmentalization of injection wounds. The controversy on the use of injection in trees is due essentially to initial mistakes that have then been rectified. Injection in palms against the red palm weevil. For palms, for decades, this technique has been employed without problems and with great efficiency against various pests, including Rhynchophorus ferrugineus, the red palm weevil (RPW). Its use has been reserved for exceptional situations either to face abnormal pest proliferation, uncontrollable by other techniques, or to implement eradication programs. Integrated eradication program. In such a program, the main aim of injection treatments is preventive. With long-persistence insecticides, the number of treatments could be greatly reduced. The resulting savings in time and money would enable the organization of the treatments of all the palms located in an infested area, and consequently the rapid eradication of the pest. New perspectives. We established that insecticides applied by injection were capable of protecting palms with only two or even one treatment per year. These results suggest a radical improvement in programs to eradicate RPW, while considerably reducing the risks to health and the environment compared with spray treatments.

South Dakota has been a leading adopter of genetically modified organism (GM) crops since their introduction in 1996. In 2009, South Dakota shared the top adoption rate with Iowa for the percentage of acres planted with Bt corn. However; South Dakota has also recently experienced a significant increase in the proportion of acres treated with insecticide. The empirical evidence presented suggests that corn, hay and sunflower production in South Dakota have experienced an intensification of insecticide use in 2007 relative to past US Census of Agriculture reporting years. This study links the proportion of acres planted for a specific crop to the proportion of total acres treated with insecticide at the county level. This approach provides insight on how changing cropping patterns in South Dakota have influenced insecticide use. Empirical results indicate that the upper-bound estimate for insecticide usage on non-Bt corn acreage increased from 38% in 2002 to all non-Bt corn acres planted in 2007. The implication of this result is that in 2007 South Dakota producers were likely treating a percentage of their Bt corn acres with insecticide. Changing cropping patterns in South Dakota are also compared to that in other states in the US Corn Belt region. It appears that the South Dakota experience is not unique and is part of a broader trend.

This review describes the major stored-product insect species and their resistance to insecticides. The economic importance of the control of those pests is highlighted with a loss of more than one billion US dollars per year worldwide. A detailed common description of species resistance throughout the world has been developed, and we observed 28 recurrent studied species involved in resistance cases disseminated on the five continents. The different mechanisms, including behavioral resistance, were studied particularly on Oryzaephilus surinamensis. The role of detoxifying enzymes and studies on the genetic resistance, involving the kdr mutation mechanisms and the transmission of the genes of resistance, are also described. A chapter clarifying definitions on cross and multiple resistance is enclosed.

Oryzaephilus mercator and O. surinamensis are stored grains and processed food pests, the latter being responsible for major economical losses. Polyacrylamide gel electrophoresis was used to analyse esterase patterns during insect development. Seven esterases, three cholinesterases, two carboxylesterases and two acetylesterases, were identified in O. mercator, one of which was proper to adults. Five esterases, of which four were cholinesterases, occurred in O. surinamensis. Strains of O. mercator and O. surinamensis were also exposed to malathion and chlorpyrifos-methyl. According to the LC50 estimates, OmLC-M and OmLA strains of O. mercator and OsLB strain of O. surinamensis were the most resistant to both insecticides. However, higher sensitivity to malathion and chlorpyrifos-methyl has also been verified in some of its esterases. Cholinesterases OmEST-1 and OsEST-5 seem to be involved in this resistance. These results suggest that organophosphate tolerance may be related to genetic variability in esterase isoenzymes.

Introduction. The effects of imidacloprid and fenobucarb insecticides on thedynamics of the psyllid Diaphorina citri and on the incidence ofCandidatus Liberibacter asiaticus (Ca. L. a.), theputative causal agent of Huanglongbing disease (HLB), were studied in a field experiment.Materials and methods. The experimental design consisted ofthree independent 0.5-ha Citrus orchards planted with disease-freeHLB-susceptible orange trees, located in a Citrus producing areaseriously affected by HLB. Imidacloprid was applied monthly to the trunks in one orchardat a rate of 0.15 g a.i.·tree–1; fenobucarb was sprayed fortnightly in a secondorchard at a rate of 250 g a.i.·ha–1. The 3rd orchard was managed as a controlwithout insecticide applications. The total number of adult D. citrispecimens and the percentages of trees harbouring psyllid eggs and 5th instar nymphs weremonitored at fortnightly intervals in each orchard. Ca. L. a. incidencewas assessed in each orchard by PCR at 5 months, 12 months and 24 months after planting.Results. Compared with the control, both the fenobucarb and imidaclopridtreatments reduced adult psyllid populations by over 90% and reduced the frequency oftrees harbouring eggs and 5th instar nymphs. Only imidacloprid treatments totallyprevented development of a new generation of adults from eggs. Two years after planting,the prevalence of Ca. L. a. was 0.939, 0.745 and 0.239 in the control andin the orchards treated with fenobucarb and imidacloprid, respectively. Discussionand conclusion. The results indicated that, although both the insecticides usedeffectively reduced D. citri populations by killing adults and nymphs andby affecting or preventing psyllid reproduction in orchards, neither of the twoinsecticide treatments totally prevented transmission of Ca. L.asiaticus. However, due to its long-lasting effect and systemic activity, the imidaclopridtreatment provided the best protection against infections, and delayed and slowed down thespread of the pathogen. Furthermore, it reduced the number of pesticide applicationsneeded and left the way open for biological integrated pest management programmes.

The impact of three different doses of botanical insecticide derived from the syringa tree, Melia azedarach and the neem tree, Azadirachta indica was tested on the behaviour of the diamondback moth, Plutella xylostella (Linnaeus). Both botanical insecticides had a significant impact on larval behaviour. At higher doses the extracts showed feeding deterrent activity, with larvae preferring the untreated sides of cabbage leaves and consuming less of the treated half of cabbage leaves. The botanical insecticides had less of an effect on the oviposition behaviour of P. xylostella moths. In laboratory and glasshouse trials, significantly fewer eggs were oviposited on the plants that had been treated with syringa extracts. Therefore, the syringa extracts appear to have a repellent effect. In contrast, when exposed to the neem extracts the moths did not discriminate between control plants and treated plants. Behavioural observation indicated that, despite the lower number of eggs oviposited on cabbage treated with syringa extracts, the moths chose cabbage treated with the highest dose of syringa more often than they chose control cabbage plants. Similar observations were found in cabbage plants treated with neem, moths chose the medium dose more often than they chose the control. Oviposition and feeding deterrent properties are important factors in pest control, and results from this study indicate that botanical insecticides have the potential to be incorporated into control programmes for P. xylostella in South Africa.

Introduction. Damage of citrus fruits by the Mediterranean fruit fly Ceratitis capitata Weid. results in economic losses in Nigeria. The majority of the citrus producers are small-holders who are yet to adopt standard citrus production practices. A trial was therefore established in a savannah zone of Nigeria with a Southern Guinea agroecology to evaluate simple fruit fly control practices. Materials and methods. The efficacy of combining cultural practices such as removal of dropped fruits, changes of harvest period, and three applications of dimethoate/cypermethrine mixture in controlling fruit fly damage was tested on sweet orange Citrus sinensis (L.) Osbeck var. Valencia Late in 2000 and 2001. Results. Fruits attacked by C. capitata increased with fruit maturity and were positively correlated with the number of dropped fruits. Insecticide applications and removal of dropped fruits significantly reduced the number of fruits attacked by the fruit flies. Similarly, early harvesting at 50% fruit ripening significantly (P < 0.05) reduced the number of fruits attacked by the fruit flies when compared with the late harvesting at 90% ripening. The interactive effects of insecticide applications and the period of harvest significantly (P < 0.05) reduced attacks on fruits. Discussions. Judicious use of insecticides, periods of harvest and removal of fallen fruits reduce fruit fly damage. Late harvest and non-removal of fallen fruits constitute fruit fly reservoirs for the re-infestation of other clean fruits. Since the tested control methods were simple, they can be adopted by small-holders for the control of fruit flies.

—The possible immune responses of insects to some abiotic agents were reviewed. These agents include insecticides, insect growth regulators, antibiotics, inert particles and miscellaneous substances of particulate and non-particulate nature. The significance of studying the immune response of insects to abiotic agents in relation to insect control, together with the link between the immune response of insects to both abiotic and biotic agents is discussed.

Introduction. En France, Cacopsylla pyri est un ravageur redouté en vergers de poiriers. La lutte contre cet insecte repose d'une part sur les traitements post-hivernaux sur adultes et œufs, d'autre part sur les traitements printaniers sur jeunes larves. Le retrait du commerce des colorants nitrés et la résistance de C. pyri aux pyréthrinoïdes utilisées contre les adultes en fin d'hiver rendent la lutte post-hivernale plus difficile, entraînant la présence au printemps de populations larvaires importantes avec parfois des échecs dans la lutte. Dans cette étude, nous avons testé l'efficacité, sur les différents stades de développement du psylle, de plusieurs insecticides utilisés seuls ou en association avec des huiles de pétrole. Matériel et méthode. Différentes populations de psylle prélevées à plusieurs dates dans différentes localités du sud-est français ont été traitées en laboratoire après migration des larves sur de jeunes plants de poiriers. Des pulvérisations d'insecticides ont été appliquées sur les différents stades larvaires L1-L2, L3-L4, L5 et œufs, alors que le stade adulte a été traité par application topique et test tarsal, notamment avec des pyréthrinoïdes, de l'abamectin, de l'amitraze et des huiles de pétrole. Résultats. L'efficacité de l'abamectin et de l'amitraze a été maximale sur les stades L1 à L4, et elle a baissé faiblement sur les larves du stade L5. Les DL50 de ces deux insecticides ont varié selon les localités et les dates de prélèvements. Quel que soit le stade de développement du psylle, les pyréthrinoïdes n'ont eu qu'une faible efficacité. Les tests avec les huiles ont fait apparaître une efficacité sur adultes par contact tarsal qui, ajoutée à leur efficacité sur jeunes larves, décrite par ailleurs, montrent l'intérêt de leur introduction dans les programmes de lutte contre C. pyri.

Onchocerciasis is a widespread disease in intertropical Africa, which, ultimately, causes irreversible blindness. The disease is transmitted by a small blackfly, Simulium damnosum (Diptera), which has aquatic larval and pupal stages. The breeding sites of the blackflies are riffles. These river reaches are the targets of the control campaign of the Onchocerciasis Control Programme in West Africa (OCP). An aquatic monitoring network covering the totality of the area exposed to the insecticide was set up to evaluate environmental impact. In this paper, we present results from the OCP 20-year period of monitoring of the ichthyofauna regularly exposed to larvicides. We do not record any measurable effects of pesticides on the CPUE, abundance of species, trophic structure, community structure or fish health. However, we detect the emergence of a number of medium-term tendencies. These tendencies may relate to climatic conditions that have a consequent effect on hydrology. Thus, we note a constant decrease in the CPUE from the beginning of the monitoring until 1995. The rivers were treated during that time until 1990 or 1993, depending on the station. But even after the treatments ended, the number of catches continued to decrease. As a result, we consider other factors to be the cause of that decline. The average level of annual discharges in this region has been decreasing regularly from the beginning of the 1970s. The production of fish fluctuates in all the rivers according to the flood rate. Important floods inundate larger areas, making greater quantities of food available, and thus improving the conditions for reproduction. The determining factor of the ichthyological stock abundance seems to depend both on the extent and the duration of the flood. In our catches, the observed effect was not immediately evident but appeared a few years later as a cumulative effect of poor hydrological conditions. An increase in the CPUE since 1996 has been related to improved hydrological conditions. In these last few years, we have observed an intensification of the basic flow leading to a ground water renewal. Furthermore, on three of the stations investigated, it appeared that the impediment of rivers (dams) could induce different and/or antagonistic effects. In some cases, we have observed that in spite of unfavourable hydrological conditions, certain species appear to be favoured by the presence of the dam. But, the damming of the river has a negative effect on other species, particularly on the coefficient of condition of migratory fishes. The impact of these factors is enhanced by the fact they exist conjointly.

Studies were carried out to compare the efficacy of insecticide schedules based on calendar intervals with those based on plant growth stages for the control of cowpea insect pests. Spray schedules based on calendar intervals and plant growth stage gave reasonable control of the pest complex and increased grain yields significantly. However, spray schedules based on plant growth stages alone were more efficient for two of the three cowpea varieties tested. This was attributed to differences in maturity periods which made spraying by regular calendar intervals slightly out of phase with attack by key insect pests. Thus, spray schedules based on plant growth stages are recommended for the control of insect pests of cowpea.

Insecticides belonging to the four major groups were bioassayed against Helicoverpa armigera Hubner collected from cotton in the Guntur region of Andhra Pradesh, India, during the 1989/90, 1990/91 and 1991/92 cropping seasons. High levels of resistance to all groups of insecticides were recorded. Tolerance to quinalphos had increased drastically in the 1991/92 season, while resistance to endosulfan, monocrotophos and carbaryl had increased moderately. The populations were also highly resistant to cypermethrin and deltamethrin and mildly resistant to fenvalerate. The resistance levels varied from season to season, thus reflecting the selection pressure created through insecticides.

In view of the losses of harvested grain incurred due to problems related to storage, marketing, transport, and handling, this paper reviews the situation on storage of food grains in developing countries. It lists the insect pests that frequently attack stored food grains in these countries and discusses strategies that would minimise the damage caused by the pests.

Five insecticides and three mixtures were tested on the cotton flea beetle (CFB), Podagricapuncticotis (Weise), the spiny bollworm (SBW), Earias insulana (Boisd.), and the cotton aphids (CA), Aphis gossypii (Glov.). The relative potency (in terms of LD50 and or LC50) for CFB followed this order: endosulfan + dimethoate > endosulfan + chlorpyrifos > dimethoate > fenvalerate > endosulfan > endosulfan + amitraz > amitraz. The LCS0 values ranged from 12. 0–1150 ppm. For SBW, the following order was obtained: fenvalerate > endosulfan + dimethoate, endosulfan + chlorpyrifos > endosulfan > dimethoate > chlorpyrifos > endosulfan + amitraz > amitraz. LC50 ranged between 0.35 and 3388 ppm. With regard to CA endosulfan + chlorpyrifos > endosulfan + dimethoate > endosulfan + amitraz > chlorpyrifos > endosulfan > fenvalerate > dimethoate > amitraz.

In general, C A was relatively tolerant to most tested insecticides when compared with the other two pests. The SBW was the most susceptible.