Integrated Pest Management Programs Research Articles

Effects of imidacloprid-induced hormesis on the development and reproduction of the rose-grain aphid Metopolophium dirhodum (Hemiptera: Aphididae).

Field populations of insect pests are affected by sub-lethal doses of insecticides, leading to hormesis. Imidacloprid is a neonicotinoid insecticide widely used to control various sucking insect pests, including aphids. In this study, the effects of sub-lethal concentrations of imidacloprid on the life table traits of the rose-grain aphid Metopolophium dirhodum (Walker) were evaluated on parental and first filial generations. The results showed that sub-lethal concentrations of imidacloprid significantly reduced the fecundity, adult longevity, and reproductive period of M. dirhodum in parental generation (F0). However, the imidacloprid-induced hormetic effects on development and reproduction were detected in the F1 generation. These hormetic effects were indicated by significantly higher adult longevity, fecundity, survival rate, intrinsic and finite rates of increase, and net reproductive rate of first filial generation (F1) of M. dirhodum. Our finding indicated that the application of sub-lethal concentrations of imidacloprid inhibited parental generation (F0), but it significantly stimulated the population growth of filial generation (F1) in the M. dirhodum. The results support the inclusion of insecticides in integrated pest management programs for managing wheat aphids.

Manifestation and dispersal of entomopathogenic nematodes in orchard ecosystem with regards to soil characters in three different zones of Chhattisgarh state

Entomopathogenic nematodes (EPNs) are round worms from the genera Steinernematid and Heterorhabditid. They are ubiquitous in nature. Survey results of the present study show that 7 samples out of 800 collected samples (0.87%), were positive for EPN which were obtained from silty loam and loamy sand soil. This is an extensive first of its kind study on EPN survey throughout the state of Chhattisgarh. The EPN were recovered from 5 of the 24 surveyed districts namely Baloda Bazar (Ber crop), Mahasamund (Mango crop), Raipur (Sapota crop, Papaya and guava), Bijapur (Mango crop), Sukma (Mango crop). The organic matter estimate from EPN recovered soils were found to be in the range of 0.56- 1.06 % with pH of slight acidic to neutral (5.6-7.1). Water holding capacity of EPNs isolated soil was 32.05 - 38.87 % and bulk density was 0.96 – 1.27 g/cm3 with moisture percentage of 4.26- 24 %. The present study shows that nematodes can be found in low moisture soil as well as high moisture soils. The results of molecular identification reveals that isolated EPN samples were identified as Heterorhabditis indica. EPNs are being investigated primarily for biocontrol purposes. There are many exotic EPN which had conflicting results in many field testing situations, most likely due to their low adaption to local agro-climatic conditions. Henceforth our quest was to look for an indigenous variety of EPN which can be used as a novel bio pesticide, our work mainly focuses on identification of local EPN strains from Chhattisgarh state which can be further used in Integrated Pest Management programme.

Berry species and crop management approaches affect species diversity and abundance of predatory mites (Acari: Phytoseiidae).

Berries comprise an economically important group of crops. Knowledge about their arthropod pests and biological control agents is important in the development of more efficient integrated pest management programs. Identification of potential biocontrol agents based solely on morphological attributes may be difficult and so molecular techniques should be incorporated. Here we studied the species diversity of predatory mites in the family Phytoseiidae, and how this diversity is affected by the berry species and crop management approaches, specifically pesticide application regimes. We sampled 15 orchards in the State of Michoacán, Mexico. Sites were selected based on berry species and pesticide regimes. Mite identification was achieved by combining morphological attributes and molecular techniques. Phytoseiidae diversity was compared amongst blackberry, raspberry and blueberry. Subsequently we studied the effect of berry species and pesticide regime on the abundance of the most prevalent phytoseiid species. We identified 11 species of phytoseiid mites. The greatest species diversity was found in raspberry, followed by blackberry and then blueberry. The most abundant species were Typhlodromalus peregrinus and Neoseiulus californicus. The abundance of T. peregrinus was significantly affected by pesticide application but not by berry species. In contrast, abundance of N. californicus was significantly affected by berry species but not by pesticide regime.

Evaluation of Insecticide Toxicity and Enzymatic Detoxification in Neonate Larvae of European Grapevine Moth, Lobesia botrana Denis & Schiff. (Lepidoptera: Tortricidae)

Lobesia botrana Denis & Schiff. (Lepidoptera: Tortricidae), also known as the European grapevine moth is a detrimental pest in grape production in Palearctic Region. Insecticides are used to control L. botrana infestation in grape-produced areas; however, repeated and intensive use of insecticide causes reduced efficacy in L. botrana management. In the present study, the efficacy of five commonly used insecticides (chlorpyrifos-ethyl, emamectin benzoate, indoxacarb, lambda-cyhalothrin, and spinosad) was evaluated in two field populations (AL and SAR) from Manisa, Turkey. In addition, detoxification enzyme activities including esterase (EST) and glutathion-S-transferase (GST) were measured via in vitro assays. LC50 values were found lower for chlorpyrifos-ethyl, emamectin benzoate, and spinosad and higher for indoxacarb and lambda-cyhalotrin in AL populations compared to SAR population. EST levels were slightly higher in AL population compared to SAR. GST levels were found higher in SAR population. However, no statistical difference was found in both detoxification enzyme activities and EST enzyme levels were higher than GST enzyme levels in both populations. Findings of the current study would help growers as well as the applicator to strategize their insecticide use in integrated pest management programs for L. botrana and possibly mitigate any insecticide resistance development.

Sequential Sampling Plans for Thrips (Thysanoptera: Thripidae) in Soybean Crops With Insecticide Applications Using Tractor or Airplane.

Sampling plans are an essential part of integrated pest management programs. Sequential sampling plans enable rapid and low-cost assessment of pest densities. Thrips are emerging pests in soybean crops, and the main method used in pest control is chemical. In soybean crops, insecticides are applied mainly using tractors or airplanes. Thus, this work aimed to determine sequential sampling plans for thrips in soybean crops with insecticide applications using a tractor or airplane. Data were collected in 56 soybean fields, and each field was 20 ha. Sampling plans were determined and validated. The lower (m0) and upper (m1) limits of the sequential sampling plans were: m0 = 1.72 and m1 = 3.43 (by tractor applications) and, m0 = 2.27 and m1 = 4.53 thrips. sample-1 (by airplane applications). The slope (S) and the lower (h0) and upper (h1) intercepts of the sequential sampling plans were: S = 2.42, h0 = -5.79, and h1 = 5.79 (by tractor applications) and, S = 3.19, h0 = -6.83, and h1 = 6.83 (by airplane applications). Sequential sampling plans allowed for correct decisions to be made in all situations using a maximum of 10 samples. The sequential plan reduced the sampling effort by over 87% compared to conventional sampling plans. Therefore, these control decision-making systems have proven feasible and advantageous for implementing integrated pest management programs for controlling thrips species in soybean crops.

Role of herbivore‐induced maize volatiles in the chemotactic behaviour of Telenomus podisi and Diceraeus melacanthus

AbstractPlants respond indirectly to herbivore injury in a species‐specific way and emit a specific blend of volatiles that are attractive to the enemies of herbivores. We evaluated whether maize plants, Zea mays L. (Poaceae), can recognize herbivory damage from a generalist stink bug, Diceraeus melacanthus Dallas (Hemiptera: Pentatomidae). This species is not a common pest in maize, but is currently found on maize crops in Brazil. We aimed to answer the following questions: (1) does D. melacanthus use maize plant volatiles for host location? (2) Do maize plant chemical volatile profiles change due to feeding by D. melacanthus? And (3) do herbivore‐induced plant volatiles (HIPVs) emitted by maize plants play a role in the foraging behaviour of the generalist stink bug egg parasitoid Telenomus podisi Ashmead (Hymenoptera: Scelionidae)? The results show that females of D. melacanthus do not use constitutive volatiles or HIPVs as host location cues. However, feeding by D. melacanthus activates maize indirect defence, inducing emission of HIPVs and attracting the herbivore's enemy. Thus, strengthening indirect defence of plants can be a strategy to protect crops in the field by recruiting natural enemies through chemical information, as an additional approach to control D. melacanthus within an integrated pest management program.

Side effects of Zataria multiflora Boiss (Lamiaceae) essential oil on predation and life table parameters of Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae)

The predatory mite, Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is one of the most promising candidates for biological control of some economically important mites and insect pests such as spider mites, whiteflies, and thrips. Western Flower Thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a severe economic pest for many crops in the world. In this study the lethal concentrations of Shirazicum thymus: Zataria multiflora Boiss (Lamiaceae) essential oil was calculated to the adult stage of the WFT. Side effects LC30 and LC50 of the essential oil were assessed on life table parameters and functional response of A. swirskii. Experiments were carried out in growth chambers at 25 ± 1 °C, 60 ± 10% RH, and 16: 8 h (Light: Dark) photoperiod. We utilized the age-stage, two-sex life table method to evaluate the life history features and population growth of A. swirskii on WFT. For assessing the functional response, the first instar of WFT was offered as prey to the adult female of A. swirskii with densities of 2, 4, 8, 16, 32, and 64. The LC50 concentration of the essential oil resulted in lower fecundity (15.05 eggs/female) in comparison with the control (19.8 eggs/female). The application of LC50 and LC30 concentrations also resulted in a significant decrease in net reproductive rate (R0) (8.9, 6.6, and 4.5 eggs per individuals), intrinsic rate of increase (rm) (0.116, 0.093, and 0.077 day -1), finite rate of increase (λ) (1.123, 1.097, and 1.079 day -1), but an increase in mean generation time (T) (18.5, 20.1, and 19.5 days) (for control, LC30, and LC50, applications, respectively). A type II functional response was detected for A. swirskii fed on WFT first instar in all treatments. Adult females of A.swirskii had the highest attack rate (a) (0.11± 0.01 h-1) and shortest handling time (1.61± 0.46h) on control treatment. In conclusion, although Z. multiflora essential oil had potential against F. occidentalis to be applied in integrated pest management programs, the lethal side effects of selected essential oil on the predatory mite, A. swirskii should be considered.

Dactylopius opuntiae (Hemiptera: Dactylopiidae) as a Diet Source for Mass Rearing Cryptolaemus montrouzieri (Coleoptera: Coccinelidae).

Although natural enemies play an important role in most integrated pest management programs, biological control agents remain poorly adopted in food production systems primarily due to the high costs associated with their implementation. Cryptolaemus montrouzieri (Mulsant, 1853) is a very promising candidate for the biological control of mealybugs. However, mass rearing of this predator is critical to provide sufficient numbers so that effective control of mealybugs can be achieved. Thus, this work focuses on mass rearing of this biological control agent under controlled conditions at T = 28 ± 1°C, RH = 70 ± 5%, and 12:12-h photoperiod L:D. This experiment was based on feeding this predator three diets: a freeze-dried artificial food source, the cactus cochineal-Dactylopius opuntiae (Cockerell, 1929), and a combination of the two diets. The fecundity recorded in the freeze-dried artificial food, D. opuntiae, and mixed diet was 2.73, 8.79, and 8.78 larvae/female, respectively. The sex ratios (male:female) of the cochineal adults that emerged on the three diets were 1:1.35, 1:1.23, and 1:1.11, respectively, for the freeze-dried artificial food, D. opuntiae, and mixed diet. The emerged adults had an average weight of 9.2mg when fed the artificial diet, 13.8mg for the D. opuntiae diet, and 9.5mg for the mixed diet, while the life cycle duration for each diet was 50.1, 43.5, and 42.3 d, respectively. At the beginning of the C. montrouzieri rearing process with 40 adults, our results indicated that an average of 1031.1 adults can be produced using D. opuntiae as the diet in a volume of 1 m3. The D. opuntiae diet is recommended due to its overall lower costs. Additionally, this study indicates that mass-rearing of C. montrouzieri can be achieved with cheaper and more readily available materials for diets, instead of purchasing a freeze-dried artificial food source.

Azadirachtin-based insecticide impairs testis morphology and spermatogenesis of the southern armyworm Spodoptera eridania (Lepidoptera: Noctuidae).

In the search for alternative tools for integrated pest management, azadirachtin, a botanical insecticide, has been used with the most promising activity against Spodoptera spp., but the mechanism of cytotoxicity on reproductive organs remains unclear. Spodoptera eridania (Stoll, 1782) is a polyphagous pest with great economic importance that has become an important target to elucidate the action of azadirachtin on the reproductive organs of insect pests, helping to understand the deleterious effects caused by its exposure. This study evaluated the effects of chronic exposure to azadirachtin on the morphology and ultrastructure of S. eridania larval testes as well as larval development. Azadirachtin exposure (6 or 18 mg a.i.L-1 ) caused a progressive increase in cumulative mortality and reduced gain in body mass after 5 days. Testicular structure indicated a reduction in their size with internal morphological changes such as spermatogonia, spermatogonial, spermatocytes and spermatid cysts in degeneration. The occurrence of cell death in germ and somatic cells was evidenced by the TUNEL technique. Electron microscopy revealed changes in cystic cells, such as cytoplasmic membrane rupture and cytoplasmic vacuolization. Chromatin compaction, changes in the rough endoplasmic reticulum and Golgi complex cisternae were observed in germ cells. Apoptotic bodies occurred between germ cell cysts. Azadirachtin damaged the testes of S. eridania larvae, and these changes compromised spermatogenesis and consequently the development of the reproductive potential of this specimen, making azadirachtin a promising botanical insecticide for application in integrated pest management programs. © 2022 Society of Chemical Industry.

Studies of SRC bio pesticide to control the insect infestation in vegetables

Biopesticides are products formulated from naturally occurring organisms such as fungi, plant and bacteria that are pathogenic or toxic to insect pests. Advantages to these products are that they have low environmental risk, low risk to nontarget organisms including mammals and beneficial insects, and can help reduce resistance to pesticides when used in an integrated pest management programme. Biopesticides were experimented on different vegetable crops from different farmers, in which it was found that Biopesticides destroys the insects that damage the crops, also increases the yield. Biopasticidase was used on brinjal, tomato and chili, in which along with pest control, the yield of brinjal increased by 8.5%, the yield of tomato by 7.3% and the yield of chili was increased by 8.08%.

Application of the Backpropagation ANN to Assess the Adoption Level of Farmers to Integrated Pest Management in the Province of Soc Trang (Vietnam)

The integrated pest management (IPM) program was implemented in 2015 and 2016 in the province of Soc Trang. The research question is whether Artificial Neural Networks (ANNs) with pattern recognition can be useful for classifying farmers for a more realistic assessment of the performance of an IPM program. To evaluate the performance of the program, three datasets were collected, including dataset S1i with 450 farmers interviewed before conducting the IPM program, S2i with 250 farmers in the pilot area (communes/villages), and S3i with 50 farmers outside the pilot area. The conventional statistical assessment method (CAM) assumes that all farmers in each dataset behave similarly related to IPM concerning the seed, spray frequency, and dosage. This means that the original datasets were used to estimate the required statistical parameters. Thus, the traditional approach wastes information hidden in all surveyed data. Based on ANN, we can classify and determine the percentage of farmers in the six groups or the level of IPM adoption (3 neutral groups and 3 active groups) as well as the actual benefits of the IPM program. ANN-based assessment method (ANN-M) has been proven to be better than CAM in evaluating the performance of the project.

Arthropod fauna on the abaxial and adaxial surfaces of Acacia mangium (Fabaceae) leaves.

Acacia mangium (Willd., 1806) (Fabales: Fabaceae) is a fast growing, rustic, pioneer species, with potential to fix nitrogen, and for programs to recover degraded areas. The objective was to evaluate the distribution and the functional diversity of interactions and the K-dominance of arthropod groups on A. mangium saplings. The number of individuals of eleven species of phytophagous insects, three bee species, and fourteen natural enemy species were highest on the adaxial leaf surface of this plant. Abundance, diversity and species richness of phytophagous insects and natural enemies, and abundance and species richness of pollinators were highest on the adaxial A. mangium leaf surface. The distribution of five species of sap-sucking hemipterans and six of protocooperating ants (Hymenoptera), with positive interaction between these groups, and three bee species (Hymenoptera) were aggregated on leaves of A. mangium saplings. Aethalion reticulatum (L.) (Hemiptera: Aethalionidae) and Bemisia sp. (Hemiptera: Aleyrodidae); Brachymyrmex sp. and Camponotus sp. (Hymenoptera: Formicidae); and Trigona spinipes Fabricius (Hymenoptera: Apidae) were the most dominant phytophagous insects, natural enemies, and pollinators, respectively, on A. mangium leaves. Knowledge of preferred leaf surfaces could help integrated pest management programs.

Symbiotic bacteria associated with entomopathogenic nematodes in the families Steinernematidae and Heterorhabditidae in biological plant protection

Entomopathogenic nematodes in the family Steinernematidae (Filipjev, 1934) and Heterorhabditidae (Poinar, 1976) include more than 90 species and are symbiotically related to bacteria in the genera Xenorhabdus (Poinar, 1979) and Photorhabdus (Boemare, 1993). These nematodes are recognized as promising agents for biological control of many insect pest species in crops. The nematodes act as vectors, allowing the bacteria to enter the insect’s body, while the bacteria, after killing the insect, provide the nematodes with continued access to food and an environment for reproduction. Xenorhabdus and Photorhabdus bacteria are closely related phylogenetically, but differ in their host specificity and production of different antibiotics and insecticidal toxins. Due to this symbiosis, they have been successfully implemented in integrated pest management programs around the world due to their strong insecticidal properties and wide range of action. This work presents a review of the symbiosis between bacteria and nematodes and their relationship in biological plant protec­tion.

EFFECT OF DIFFERENT CONCENTRATIONS OF EPNS AND MALATHION ON SUGARCANE WHITE GRUBS, Heteronychus licas (Coleoptera: Scarabaeidae) MORTALITY

Sugarcane, Saccharum officinarum L. is one of the major commercial crops grown in Eswatini. However, pest and diseases are pivotal to the decrease in yield output in the country. Sugarcane white grubs (SWG), Heteronychus licas Klug (Coleoptera: Scarabaeidae) are amongst the important pests of sugarcane in the country. Entomopathogenic nematodes (EPNs) were found to be effective in controlling both soil borne as well as above ground insect pests. The current study determined the effect of different concentrations of Malathion and EPNs on the mortality of SWG. SWG larvae were dipped in different concentrations (0, 0.625, 1.25, and 2.5 g/L) of malathion and (0, 200, 400, and 600 IJ/insect) EPNs. SWGs were also exposed to the same concentrations in soil bioassays. Results obtained in the bioassays showed that Steinernema yirgalemense at 600 IJs/insect (85.4%) gave the highest mortality which was not significantly different from S. yirgalemense at 400 IJs/insect (72.9%). The Malathion concentrations gave 0, 79.2, 83.3 and 89.6% mortality for 0, 0.625, 1.25 and 2.5g/L of Malathion, respectively. Results obtained in the soil bioassays showed that Steinernema yirgalemense, at 600 IJs/insect (80.5%), provided higher (p < 0.05) mortality of the H. licas larvae which was not significantly different from S. yirgalemense at 400 IJs/insect (70.2%). The Malathion concentrations gave 0, 83.3, 85.4 and 87.5% mortality for 0, 0.625, 1.25 and 2.5g/L of Malathion, respectively. The results indicated that both EPN and Malathion were tested were effective against H. licas larvae. Steinernema yirgalemense at 400 IJs/insect and Malathion at 0.625g/L can effectively H. licas larvae but large-scale field trials are recommended to demonstrate the potential use of the biocontrol agent within integrated pest management programs.

Evaluating a decade (2011–2020) of integrated forest pest management in the United States

AbstractTo sustain healthy forests in the United States, the USDA Forest Service, Forest Health Protection and cooperators utilize integrated pest management (IPM) programs to prevent, suppress, and eradicate insect and disease outbreaks affecting trees across all land ownerships. Forest pest management projects supported by federal funding from 2011 to 2020 were assessed to determine the most frequently used project types, IPM strategies and tactics, identify the dominant forest pests and associated hosts managed, and identify the most comprehensive forest IPM programs in practice. Forest pest management projects were obtained primarily from two centralized databases and included 2,416 projects that treated a total of 2,284,624 ha. Two project types accounted for most of the forest pest projects (suppression: 63% and prevention: 30%). Native forest pests were targeted more (79%) than non-native pests (21%) in these projects; however, non-native pests accounted for more treatment areas. Forest pest projects were directed mostly at phloem-feeding insects (70%) and subsequently followed by foliage feeders (10%), sap feeders (6%), and all other pest groups (each < 5%), including diseases. Four IPM control strategies (silvicultural: 32%, semiochemical: 22%, chemical: 21%, and physical/mechanical: 18%) accounted for most of the forest pest projects. Foliage feeders possessed the most comprehensive IPM programs that adopted two or more types of control tactics. Few pest programs incorporated microbial/biopesticide control strategies and this represents an area where research is needed. In addition, better-centralized records are needed for genetic control projects, treatment efficacy, and survey and technical assistance activities.

Effect of Artificial and Corn Leaves Diets on Development, Survival and Reproduction of <i>Spodoptera frugiperda</i> (Lepidoptera: Noctuidae) in Sierra Leone

The use of artificial diets to mass reared insect stock under laboratory conditions, promotes knowledge about the biology, behavior, and nutritional requirements of insects; with such information being fundamental for the formulation of efficient integrated pest management programs (IPM) strategies. However, the artificial diets used for rearing Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in the laboratory in this study, do not contain wheat germ, used for routine laboratory rearing. The aim of this study was to compare food preference and consumption by S. frugiperda larvae, as well as evaluate insect developmental parameters in the standard diet and the bean-based diets under laboratory conditions. Four artificial diets were used: a standard diet based on broad beans (Phaseolus vulgaris L.) used to rear S. frugiperda (D1), a diet with the substitution of two types of beans, cowpea (Vigna unguiculata L.) (D2) and pigeon pea (Cajanus cajan L) (D3); and a diet of fresh corn leaves (D4), the host plant of the pest species. Using a multiple-choice test, we observed that the larvae preferred diets D4 followed by D1. The relative consumption rate (RCR), relative growth rate (RGR), relative metabolic rate (RMR), approximate digestibility (AD), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), and the metabolic cost (CM) for S. frugiperda fifth instar larvae varied among diets. The diet D4 resulted in better ingestion, digestion, assimilation, and conversion of food, but with a metabolic cost to assimilate the food. The different bean varieties present in the diet influenced larval length, larval periods, larval survival, pupal periods, sex ratio, pupal weight, and pupal survival; but fecundity and longevity of adults were not affected. The different bean-based diets did positively influence population growth, with the most outstanding being D4. From the results of this study, the most adequate diet for rearing S. frugiperda in the laboratory is D4.

Efficacy of Bt Toxins and Foliar Insecticides Against Bollworm, Helicoverpa zea (Boddie), in Dried Flower Corollas of Cotton

Foliar insecticides and insecticidal protein from Bacillus thuringiensis (Bt) in transgenic cotton are common tools used for bollworm management in cotton. Efficacy of Bt proteins and foliar insecticides can be dependent upon larval location in the plant canopy and time of year. Floral structures are known to be a common food source for bollworm. Floral components can complicate bollworm control with foliar insecticides and transgenic cotton by protecting larvae from contact with formulated insecticides and lower concentrations of Bt proteins. Mortality was measured to evaluate the effects of Bt expression and foliar insecticides in flowers of non-Bt, two-gene Bt, and three-gene Bt cotton varieties. Expression of Bt protein in white flowers provided some efficacy after three days. Bollworm mortality at three days after infestation was less than 50% for all varieties in an unsprayed environment. Larval mortality on Bollgard 3 flowers was higher than that on Bollgard II flowers. Surviving larvae feeding on Bollgard 3 flowers weighed less than larvae that fed on Bollgard II flowers, and larvae that fed on Bollgard II flowers weighed less than those that fed on non-Bt flowers. The use of chlorantraniliprole or methoxyfenozide + spinetoram provided some control of bollworms three days after application to wilting flower corollas (bloom tags). Mortality ranged from 41.9% following application of chlorantraniliprole to 61.0% following application of methoxyfenozide + spinetoram. Results from this study will be used to improve integrated pest management programs for bollworm management in cotton.

Effect of Habrobracon hebetor (Hymenoptera: Braconidae) Release on Moth Infestation in Stored Tobacco

HIGHLIGHTS The H. hebetor parasitoid is effective to control the population of Ephestia spp. The potential of H. hebetor in stored tobacco is recorded for the first time in Brazil. H. hebetor can be part of an integrated pest management program in stored tobacco.

Gamma-radiation of Glossina palpalis gambiensis revisited: effect on fertility and mating competitiveness

African animal trypanosomoses are vector-borne diseases that cause enormous livestock losses in sub-Saharan Africa, with drastic socio-economic impacts. Vector control in the context of an area-wide integrated pest management program with a sterile insect technique component requires the production of high-quality sterile male tsetse flies. In our study, we evaluated the effect of irradiation on the fecundity of Glossina palpalis gambiensis to identify the optimal dose that will induce maximum sterility while maintaining biological performance as much as possible. In addition, male mating performance was evaluated in semi-field cages. The irradiation doses used were 90, 100, 110, 120, 130, 140, and 150 Gy, and untreated males were used as the control. The results showed that pupal production and emergence rates were higher in batches of females that had mated with fertile males than in those that had mated with irradiated males with any experimental dose. A dose of 120 Gy administered to male flies induced 97-99% sterility after mating with virgin females. For the semi-field cage experiments, males irradiated with 120 Gy showed good sexual competitiveness as compared to fertile males and those irradiated with 140 Gy, considering the level of filling of spermatheca and the number of pairs formed. The optimal radiation dose of 120 Gy found in this study is slightly different from the traditional dose of 110 Gy that has been used in several eradication programmes in the past. The potential reasons for this difference are discussed, and an argument is made for the inclusion of reliable dosimetry systems in these types of studies.

Biology and Management of Lesser Mealworm Alphitobius diaperinus (Coleoptera: Tenebrionidae) in Broiler Houses

Abstract Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), the lesser mealworm, is a ubiquitous generalist 
pest of poultry broiler and layer facilities, originating in southern Africa and now found worldwide. They spend their full life cycle within the litter and manure of poultry, causing structural damage to poultry houses, injuring birds, and acting as a reservoir for several avian pathogens, notably Salmonella spp. and Escherichia coli. Management commonly consists of spraying walls and floors of poultry houses with organophosphates, pyrethroids, neonicotinoids, or spinosyns between flocks, and periodic removal and replacement of litter. Populations have been observed to become resistant to specific insecticides after ca. 10 yr of consistent use and exhibit cross resistance to insecticides of the same mode of action. Alternative cultural and biological control methods have been identified but are not currently implemented. More research is needed regarding the economic impact of A. diaperinus, the mechanisms of its insecticide resistance, and patterns and mechanisms of colonization for effective integrated pest management programs to be devised and implemented.