Pest Abundance Research Articles

Response of the soft scale insect Parthenolecanium corni and its natural enemies on honeylocust trees to urban conditions

Urban habitats can alter tree physiology in ways that make trees more susceptible to insect pests. We examined how urban conditions (e.g., impervious surfaces and warming) affected the soft scale insect, European fruit lecanium, Parthenolecanium corni Bouché (Hemiptera: Coccidae) and the health of thornless honeylocust trees (Gleditsia tricanthos L. var. inermis) in Indianapolis, Indiana, USA. Hot and cool study sites were selected based on surface air temperatures obtained from thermal LANDSAT-8 images overlaid against a map of honeylocust tree locations. Based on temperature probe data, study trees located in hot sites had mean average daily temperatures up to 1.56 °C and 1.79 °C warmer than cool sites in 2019 and 2020, respectively. We hypothesized that abundance and fecundity of scale insects would be higher on trees in hot sites and those surrounded by more impervious surface cover within a 20 m radius. Although our data supported these hypotheses, impervious surface cover predicted more of the variation in abundance and fecundity of scale insects in hot sites compared to cool sites. Rates of parasitism were not affected by impervious surface cover or whether the site was from a hot or cool location. However, we found strong density dependence in parasitism of scale insects in both hot and cool sites when scale densities were at or below the levels present in cool sites. This suggests that lower densities of scale insects were associated with a positive numerical response of parasitoids, a necessary prerequisite for population regulation by top-down effects. In contrast, this numerical response was lacking at the higher densities of scales found on trees located in hot sites where, presumably bottom-up factors like water-stress increased the fecundity of scale insects. These findings add to a growing body of evidence linking rising global temperatures with increased pest abundance in ways that cannot be mitigated by local populations of natural enemies.

Flowering plants in open tomato greenhouses enhance pest suppression in conventional systems and reveal resource saturation for natural enemies in organic systems

Vegetable production in open greenhouses is often associated with high inputs of synthetic pesticides. Introducing flowering plants into such greenhouses may promote the top-down pest suppression by natural enemies and reduce the reliance on pesticide use. However, it is not known how effective this practice is in organically and conventionally managed greenhouse crops. We assessed the influence of introducing flowering plants into open greenhouses with organically and conventionally managed tomato crops on the abundance of pests, natural enemies (NE), pollinators, and crop yield. We monitored tomato crops during two years in two greenhouses at four organic farms and four conventional farms that used integrated pest management (IPM). On each farm one greenhouse contained flower islands of basil (Ocimum bacilicum), marigold (Tagetes patula) and alyssum (Lobularia maritima), and the other greenhouse served as a control. Organic farms had yields comparable to conventional farms, a lower abundance of pests, less pest injury, and a higher abundance of NE. The cumulative pest:NE ratio was 9 for organic and 38 for conventional management. The effect of introducing flowering plants on arthropods depended significantly on the type of farm management. Conventionally managed tomato crops in greenhouses with seven flower islands per 100 m2 had 18% lower pest abundance compared to the control greenhouses without flowers, while flower islands did not significantly influence arthropod abundances in organically managed tomato crops. Tomato plants had a higher abundance of pests than the three introduced plant species in conventionally managed greenhouses, while marigold had a higher abundance of pests than tomato in organically managed greenhouses. Alyssum supported a relatively low pest abundance and high abundance of NE and pollinators. Our findings indicate that NE in IPM-conventionally managed greenhouses can benefit from resources provided by flowering plants, resulting in reduced pest abundance, while in organically managed greenhouses the conditions are already favourable for the suppression of pests and addition of floral resources does not further improve the effectiveness of NE. This finding highlights the potential of agroecological and organic management to reduce the reliance on synthetic pesticides without yield reduction.

Efficacy of lure mixtures in baited traps to attract different fruit fly species in guava and vegetable fields.

Fruit flies (Diptera: Tephritidae) are major pests of fruits and vegetables worldwide. We measured the efficacy of attractive lure mixtures in baited traps on naturally-occurring fruit flies in commercial mosaic guava and vegetables fields in Pakistan. We tested three mixtures (methyl-eugenol [ME] and cue lure [CL]; GF-120 and methyl eugenol; and GF-120 and cue lure) in eleven ratios: 0:100, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 90:10, and 100:0. We recorded three fruit fly species: Bactrocera zonata was the most abundant in baited traps, followed by Bactrocera dorsalis, while Zeugodacus cucurbitae was significantly less attracted to baited traps. We also found that the most attractive mixture and ratio varied among species: B. dorsalis was most attracted by 40CL:60ME, while B. zonata was most and equally attracted by 100ME, 10CL:90ME, 20CL:80ME, 30CL:70ME, and 40CL:60ME. Finally, Z. cucurbitae was most attracted by 10CL:90ME, which resulted in the highest total number of flies counted in 10CL:90ME-baited traps. Mixtures with GF-120 were less attractive to all three species. Our results suggest that lure mixtures in baited traps influence the attraction of fruit flies in a species-specific way. This needs to be considered in the integrated pest management of multiple species of fruit flies simultaneously. If Bactrocera species are most damaging and abundant, a 40CL:60ME mixture in baited traps will likely be most effective to reduce pest abundance and crop damage. However, if Z. cucurbitae is the main pest target causing most crop damage and yield loss, 10CL:90ME-baited traps will be a more effective in their monitoring and management.

Are pests adapting to the push-pull system? Ecologically intensified farms in Kenya maintain successful pest control over time

Ecological intensification utilizes biodiversity to maintain agricultural yields while reducing negative environmental impacts. While pest management is a common goal of ecological intensification, studies examining ecologically intensified pest management systems over longer time scales are rare. Using the push-pull system in Western Kenya, we examine whether pest abundance (for both insects and parasitic weeds) and yield vary with time since a given push-pull field was established. With a total of 1880 data points from 476 unique farmers and 24 cropping seasons, we found that pests declined with time since establishment in both push-pull and nearby control fields, while yield improved with time since establishment in push-pull fields. Although this study did not directly address mechanisms, it seems likely that pests in the push-pull system are not successfully adapting to overcome its pest management effects given the continued declines in pest abundance over time. Our data suggest that ecologically intensified agriculture may be resilient against pest adaptation over time, maintaining consistently high yields.

Continent-wide evidence that landscape context can mediate the effects of local habitats on in-field abundance of pests and natural enemies.

Landscape-scale factors known to influence in-field abundance of pest herbivores and their natural enemies, but little is known about effects that operate through the shorter-range influences exerted by habitats immediately adjacent to crop fields.This study first compared the abundance of brassica insect pests and their natural enemy arthropods in 24 spatially independent brassica vegetable fields across southern Australia. An 'edge effect' index was used to compare the abundance of each taxon in the field center with abundance in areas of the crop adjacent to differing habitats. Then, three landscape properties: landscape composition, edge density, and connectivity of diverse crop and non-crop habitats were analyzed at five scales up to 5km from these focal field centers to assess longer-range influences on arthropod abundances in field centers and on the edge effects.Edge effect of adjacent woody vegetation promoted ladybirds and reduced diamondback moth and whiteflies. Conversely, the presence of crops and pastures immediately adjacent to focal crop fields reduced whiteflies and aphids but with no effect on natural enemies.Effect of landscape composition and connectivity on arthropod abundance at field center found promotion of aphids (cabbage aphid and green peach aphid) by woodland in the landscape.Effect of landscape properties on the edge effects of adjacent habitats was contrasting; strengthened (landscape composition and edge density on edge effect of crops, pasture and woody vegetation in reducing diamondback moth and whiteflies) as well as weakened (edge density and landscape connectivity on edge effect of crops, pasture and woody vegetation in reducing diamondback moth on diamondback moth, whiteflies and aphids, and promoting ladybirds). Synthesis and applications: Findings of this geographically extensive study help define the level of pest risk associated with sites as well as suggest potential interventions such as establishment or restorations of woody vegetation adjacent to crop fields that could reduce risk.

Influence of Different Tillage Systems on Abundance and Dynamics of Pests in Maize Crop

The abundance and dynamics of pests in maize crop are influenced by the tillage system. The research has been done at Research and Development Station for Agriculture Turda (RDSA Turda) in order to estimation the insect populations in conventional tillage (plowing) and minimum tillage system (with chisel variant). The research consisted of observations and determinations on the monitoring, abundance and dynamics of the most common species pests of maize crop: Diabrotica virgifera virgifera LeConte, Autographa gamma L. and Agrotis segetum Den. & Schiff. The pests monitoring, with economically importance for maize crop was evaluated using F-1 pheromone traps, with synthetic sex pheromones (atraGAM- 9, atraSEG-21 and atraVIRG). By minimizing the tillage, there has been an increase in the pest population, especially in Diabrotica virgifera virgifera LeConte. An almost perfect synchronization of the first generation with the optimal threshold of specific temperatures for insect biology was observed in the three monitored species. This meens even if, these mechanisms were formed over the course of evolution exist a permanent adaptations of insects to climate changes.

Diversity and abundance of insect pests in stored rice under two agro-climatic zones of West Bengal and Tripura

Diversity and abundance of insect pests in stored rice under two agro-climatic zones of West Bengal and Tripura

Seasonal abundance of major insect pests of potato (Solanum tuberosum) and their natural enemies in Karnataka, India

It is essential to know the seasonal occurrences of various pests of potato along with their natural enemies so that timely management practices could be advised to farmers to avoid losses. Therefore, field studies on seasonal incidence of major insect pests of potato and their natural enemies were carried out at the All India Co-ordinated Research Project on Potato, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, India during Kharif 2016 and 2017; and at Hangaraki, a village near Dharwad during Rabi 2016-17 and 2017-18. The observations on the seasonal abundance of potato insects, mites, and their natural enemies were recorded at weekly intervals starting from 20 days after the emergence of the plant till harvest. These observations were made under unprotected conditions. During Kharif season, the sucking pests were active from July second week and continued up to harvesting of the crop and the maximum pest population was observed during August second week to September first week. The peak activity of the shoot borer, Leucinodes orbonalis Guenee was noticed during the 35th Meteorological Standard Week (MSW) (i.e., August). The maximum population of defoliator, Spodoptera litura (Fab.) was noticed during 34th MSW. The higher populations of coccinellid beetles and spiders were recorded during 35th MSW while chrysopid activity was maximum during 36th MSW (September). During Rabi season, the sucking pests were active from October second week and attained peak during the second and third week of November. The maximum activity of aphids and leafhoppers was noticed during the 46th and 47th MSW (November), respectively. The highest incidence of thrips was recorded during the 48th MSW. The peak population of whiteflies and mites was recorded during the 46th and 45th MSW, respectively. The peak activity defoliator and shoot borer were noticed during the 45th and 46th MSW, respectively. The chrysopid activity was maximum during 46th and 47th MSW.

Diverse agricultural landscapes increase bat activity and diversity: Implications for biological pest control

Diverse landscapes consisting of mixed crops are expected to support higher biological control, while also contributing to maintain farmland biodiversity. Although bats are known as predators of many farming pests, few studies to date have investigated how their foraging activity may enhance natural pest control.Here, we tested the hypothesis that crop mosaics would provide a temporal continuity in prey availability for bats, ultimately resulting in higher biological control. We sampled bat activity and diversity, and the abundance and damage of three major pests of vineyards, maize, and pine plantations, in both simple and diverse landscapes mixing the three production types. Bat species richness and total activity were higher in vineyards and pine plantations located within diverse landscapes. Bat foraging activity also peaked within diverse landscapes. In vineyards, moth abundance decreased with bat species richness. In pine plantations, pest damage decreased with bat foraging activity. In maize fields, pest abundance and damage increased with bat richness and activity longer-term investigations would be necessary to assess their actual effectiveness. Our study advocates for promoting a diversity of coexisting crops within agricultural landscapes to enhance bat activity and diversity, which in turn would sustain higher biological control and bolster biodiversity conservation in farmland.

Thermohygrometric Climate, Insects and Fungi in the Klosterneuburg Monastic Library

The abundance of insect and fungal pests under a changing climate may threaten historic interiors, libraries and museums, with warmer, potentially more humid winters. This work examines local and indoor climate, insects and fungi in a historic library near Vienna. It reveals a mostly dry and cool environment for the storage of books, but few visitors to induce changes. Temperature and relative humidity have been monitored for 12 months (2021-07/2022-07), with 14 monitors positioned insect traps (blunder traps and some pheromone traps). Fungi in air, on surfaces and in settled dust were also sampled. Winter temperatures in library cupboards and behind shelves were slightly warmer (~1 °C) and more humid than in the library environment. Over the last decade there have been infestations of the biscuit beetles (Stegobium paniceum) but since treatment with sulfuryl difluoride, Anthrenus sp. have dominated. Silverfish are also present, but only in one corner. Fungal outbreaks have also been found, but over five years fungi in air samples have shifted from Penicillium commune and P. chrysogenum to Aspergillus sp. The stable environment at Klosterneuburg is suitable for books, yet insects and mould present suggests vigilance remains necessary, as some microenvironments (e.g., cupboards) can be at risk and there may be materials with high water content, hygroscopic or of nutritional value.

Stink Bug (Hemiptera: Pentatomidae) Occurrence, Reproduction, and Injury to Fruit in an Organic Tomato Crop Bordered by Sorghum

Border rows of grain sorghum were planted along two to four sides of an organic Granadero tomato crop in North Florida to reduce fruit injury caused by native and invasive stink bugs. During the 2-yr study, 14 species of stink bugs were encountered, six only in sorghum: Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae), Thyanta spp., Oebalus pugnax (Fabricius), Chinavia hilaris (Say), C. pensylvanica (Gmelin), and Mormidea pama (Rolston). There were four species only in tomato: Euschistus obscurus (Palisot de Beauvois), E. tristigmus (Say), E. ictericus (L.), and Arvelius albopunctatus (De Geer). The three most abundant pests in tomato were collected in both crops: Nezara viridula (L.), Euschistus servus (Say), and E. quadrator Rolston, along with Proxys punctulatus (Palisot de Beauvois). Nezara viridula and P. guildinii were the most abundant stink bugs on sorghum. The border rows of sorghum did not reduce the total number of stink bug adults or nymphs in the tomato crop, although many more stink bug adults were captured in sorghum than tomato when the sorghum panicles were in the milk to soft dough stage. Generally, 30% of the females in the sorghum and tomato crops were mated and contained more than 15 eggs, indicating they could generate a considerable number of nymphs. Tomato fruit from the plot with sorghum border rows had significantly more punctures than fruit from the plot without sorghum. The stink bugs frequently probed and blemished tomato fruit in all stages of ripeness but fruit covered with probing sites were nevertheless suitable for human consumption.

Local and landscape factors determining the abundance and richness of insect pests and arthropod predators in Bt and non-Bt soybean

Agricultural landscapes of the Pampas and Campos biome have changed considerably due to the expansion of annual crops over non-crop areas, soybean seeding and the adoption of lepidopteran-resistant varieties (Bt technology). These changes have a great impact on predatory and phytophagous arthropods, which have been scarcely studied in Uruguay. The following aspects were evaluated: (a) the effect of vegetation cover composition (landscape factor), Bt technology (varieties expressing Cry1Ac protein) and field margins (local factors), on the abundance of the main pests and predators of soybean; b) the role of refuge areas (non-Bt soybean) in determining the abundance and richness of arthropod predators in Bt soybean crops, and c) the effect of Cry1Ac protein on the biology, reproduction and feeding behavior of Piezodorus guildinii (Hemiptera: Pentatomidae). In the northern Uruguayan littoral, during two years, predators and pests were sampled in 90 commercial non-Bt and Bt soybean fields and refuge areas. Biological and reproductive parameters of P. guildinii fed with Bt soybean pods and their possible effect on feeding behavior were evaluated using the electrical penetration graph technique. The main results obtained were: a) i. Bt soybean presented lower abundance of defoliating lepidoptera, without affecting predator abundance; ii. Soybean predators’ abundance was negatively related to the proportion of this crop in the landscape, but positively related to natural grassland and other crops; iii. Predators’ abundance between margins and within soybean fields was positively associated; b) Bt predators’ abundance and richness was positively associated with their values in refuge areas, evidencing for the first time their role in the conservation of beneficial fauna; c) biological and reproductive parameters and feeding behavior of P. guildinii were not affected by the ingestion of Cry1Ac protein expressed in Bt soybean pods. These results contribute to the possibilities of ecological intensification designs of national and regional production systems through pest management approached from a landscape perspective.

Olfactory Gene Families in Scopula subpunctaria and Candidates for Type-II Sex Pheromone Detection

Scopula subpunctaria, an abundant pest in tea gardens, produce type-II sex pheromone components, which are critical for its communicative and reproductive abilities; however, genes encoding the proteins involved in the detection of type-II sex pheromone components have rarely been documented in moths. In the present study, we sequenced the transcriptomes of the male and female S. subpunctaria antennae. A total of 150 candidate olfaction genes, comprising 58 odorant receptors (SsubORs), 26 ionotropic receptors (SsubIRs), 24 chemosensory proteins (SsubCSPs), 40 odorant-binding proteins (SsubOBPs), and 2 sensory neuron membrane proteins (SsubSNMPs) were identified in S. subpunctaria. Phylogenetic analysis, qPCR, and mRNA abundance analysis results suggested that SsubOR46 may be the Orco (non-traditional odorant receptor, a subfamily of ORs) of S. subpunctaria. SsubOR9, SsubOR53, and SsubOR55 belonged to the pheromone receptor (PR) clades which have a higher expression in male antennae. Interestingly, SsubOR44 was uniquely expressed in the antennae, with a higher expression in males than in females. SsubOBP25, SsubOBP27, and SsubOBP28 were clustered into the moth pheromone-binding protein (PBP) sub-family, and they were uniquely expressed in the antennae, with a higher expression in males than in females. SsubOBP19, a member of the GOBP2 group, was the most abundant OBP in the antennae. These findings indicate that these olfactory genes, comprising five candidate PRs, three candidate PBPs, and one candidate GOBP2, may be involved in type II sex pheromone detection. As well as these genes, most of the remaining SsubORs, and all of the SsubIRs, showed a considerably higher expression in the female antennae than in the male antennae. Many of these, including SsubOR40, SsubOR42, SsubOR43, and SsubIR26, were more abundant in female antennae. These olfactory and ionotropic receptors may be related to the detection of host plant volatiles. The results of this present study provide a basis for exploring the olfaction mechanisms in S. subpunctaria, with a focus on the genes involved in type II sex pheromones. The evolutionary analyses in our study provide new insights into the differentiation and evolution of lepidopteran PRs.

Diversity and Abundance of Associated Insect Pests in Stored Dry Cocoa Beans of Southwest Nigeria

Cocoa bean is a vital raw material in the production of beverage, animal feed, medicines and cosmetics which had played significant importance in Nigerian revenue prior to oil discovery. Its production has declined due to a number of factors among which are quantitative and qualitative losses by insect pests. Diverse species of insects attack dry cocoa beans in store and their pest status needs to be determined for effective control. This study examined diversity and abundance of emerging insect pests from collected cocoa samples in locations from Southwestern Nigeria. Four cocoa producing states namely Ekiti, Ondo, Osun and Oyo were chosen for this study. Four towns/villages were selected in each state from where1kg of dry cocoa beans each was collected from four cocoa stores/warehouses and bulked to represent the town/village. 750g of the beans was weighed in improvised culture cage in four replicates for each location. The experiment was laid out in a Completely Randomized Design at the Entomology laboratory of CRIN, Ibadan. Emerging insect species were counted, identified and added at thirty days interval for 120days. Ephestia cautella and Corcyra cephalonica were more abundant in all locations than populations of Plodia intepuctuella, Araecerus fasciculatus and Tribolium casteneum.

Can immune gene silencing via dsRNA feeding promote pathogenic viruses to control the globally invasive Argentine ant?

Pest control methods that can target pest species with limited environmental impacts are a conservation and economic priority. Species-specific pest control using RNA interference is a challenging but promising avenue in developing the next generation of pest management. We investigate the feasibility of manipulating a biological invader's immune system using double-stranded RNA (dsRNA) in order to increase susceptibility to naturally occurring pathogens. We used the invasive Argentine ant as a model, targeting the immunity-associated genes Spaetzle and Dicer-1 with dsRNA. We show that feeding with Spaetzle dsRNA can result in partial target gene silencing for up to 28days in the laboratory and 5days in the field. Dicer-1 dsRNA only resulted in partial gene knockdown after 2days in the laboratory. Double-stranded RNA treatments were associated with significant gene expression disruptions across immune pathways in the laboratory and to a lower extent in the field. In total, 12 viruses and four bacteria were found in these ant populations. Some changes in viral loads in dsRNA-treated groups were observed. For example, Linepithema humile Polycipivirus 2 (LhuPCV2) loads increased after 2days of treatment with Spaetzle and Dicer-1 dsRNA treatments in the laboratory. After treatment with the dsRNA in the field, after 5days the virus Linepithema humile toti-like virus 1 (LhuTLV1) was significantly more abundant. However, immune pathway disruption did not result in a consistent increase in microbial infections, nor did it alter ant abundance in the field. Some viruses even declined in abundance after dsRNA treatment. Our study explored the feasibility of lowering a pest's immunity as a control tool. We demonstrate that it is possible to alter immune gene expression of pest species and pathogen loads, although in our specific system the affected pathogens did not appear to influence pest abundance. We provide suggestions on future directions for dsRNA-mediated immune disruption in pest species, including potential avenues to improve dsRNA delivery as well as the importance of pest and pathogen biology. Double-stranded RNA targeting immune function might be especially useful for pest control in systems in which viruses or other microorganisms are prevalent and have the potential to be pathogenic.

Effectiveness of Some Chemical Pesticides Against Arthropod Pests of Ornamental Plant

The study was conducted with seven chemical pesticides to control the arthropod pests of some ornamental plants during November 2017 to May 2018 at Gazipur in Bangladesh. Pesticides were applied following company recommended dose, more than recommended dose, farmers’ practicing dose and below farmers’ practicing dose. The pesticides Actara 240SC (Thiamethoxam) and Abom 1.8EC (Abamectin) were applied @ 1.0, 1.25 (farmers’ practice), 1.5 (recommended) and 1.75 ml/L water on rose plants to control aphid and spider mite. Effectiveness of Roxin 40 EC (Dimethoate) @ 0.5, 0.75 (farmers’ practice), 1.0 (recommended) and 1.25 ml/L water was evaluated against aphid attacking tuberose. Actara 25 WG (Thiamethoxam) @ 0.1, 0.2(farmers’ practice), 0.25 (recommended) and 0.3 g/L water was sprayed to control marigold aphid. Tundra 20 SP (Acetamiprid 20%) was sprayed to control rose thrips @ 0.25, 0.5 (farmers’ practice), 0.75 (recommended) and 1.0 g/L water. Effectiveness of Liquor 1.8 EC (Abamectin) against gladiolus thrips was tested @ 1.75, 2.0 (farmers’ practice), 2.5 (recommended) and 2.75ml/L water. Feniton 50 EC (Fenitrothion) was applied to control dahlia mealy @ 1.5, 1.75 (farmers’ practice), 2.0 (recommended) and 2.5 ml/L water. Abundance of the arthropod pests was compared with control (untreated plant) at 1, 3 and 7 days after treatment. The tested pesticides significantly reduced pest population and the recommended dose of the pesticides revealed higher efficacy than that of farmers’ practice.
 Bangladesh J. Agril. Res. 45(3): 261-268, September 2020

Biological control interventions reduce pest abundance and crop damage while maintaining natural enemies in sub-Saharan Africa: a meta-analysis.

Insect pests are a major challenge to smallholder crop production in sub-Saharan Africa (SSA), where access to synthetic pesticides, which are linked to environmental and health risks, is often limited. Biological control interventions could offer a sustainable solution, yet an understanding of their effectiveness is lacking. We used a meta-analysis approach to investigate the effectiveness of commonly used biocontrol interventions and botanical pesticides on pest abundance (PA), crop damage (CD), crop yield (Y) and natural enemy abundance (NEA) when compared with controls with no biocontrol and with synthetic pesticides. We also evaluated whether the magnitude of biocontrol effectiveness was affected by type of biocontrol intervention, crop type, pest taxon, farm type and landscape configuration. Overall, from 99 studies on 31 crops, we found that compared to no biocontrol, biocontrol interventions reduced PA by 63%, CD by over 50% and increased Y by over 60%. Compared to synthetic pesticides, biocontrol resulted in comparable PA and Y, while NEA was 43% greater. Our results also highlighted that the potential for biocontrol to be modulated by landscape configuration is a critical knowledge gap in SSA. We show that biocontrol represents an effective tool for smallholder farmers, which can maintain yields without associated negative pesticide effects. Furthermore, the evidence presented here advocates strongly for including biocontrol practices in national and regional agricultural policies.

Range expansion and population dynamics of Bactrocera carambolae in Roraima, Brazil

The carambola fruit fly Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae) is the main pest that threatens Brazilian fruit production, and can cause serious economic losses. Native to southeast Asia, B. carambolae was introduced in Brazil in 1996 and is currently found in the states of Amapá, Roraima and northern Pará, where an eradication program is underway. In this study, we studied the range expansion of B. carambolae and the association of climate with seasonal dynamics in Roraima, Brazil, from January 2013 to December 2020. Monitoring of B. carambolae adults was carried out through Jackson and McPhail trapping. The highest densities of B. carambolae occurred in the northeast region of Roraima. Low densities occurred in central Roraima, and a single outbreak was observed in south Roraima in 2014, but it was eradicated. Pest abundance was positively correlated with air relative humidity. These results can assist with control efforts and eradication programs of B. carambolae by indicating the periods with higher pest pressure and potential regions for pest establishment. This study will help to improve strategies for surveillance and host fruit transport.

Earlier flowering of winter oilseed rape compensates for higher pest pressure in warmer climates

Abstract Global warming can increase insect pest pressure by enhancing reproductive rates. Whether this translates into yield losses depends on phenological synchronisation of pests with their host plants and natural enemies. Simultaneously, landscape composition may mitigate climate effects by shaping the resource availability for pests and their antagonists. Here, we study the combined effects of temperature and landscape composition on pest abundances, larval parasitism, crop damage and yield, while also considering crop phenology, to identify strategies for sustainable management of oilseed rape (OSR) pests under warming climates. In all, 29 winter OSR crop fields were investigated in different climates (defined by multi‐annual mean temperature, MAT) and landscape contexts in Bavaria, Germany. We measured abundances of adult pollen beetles and stem weevil larvae, pollen beetle larval parasitism, bud loss, stem damage and seed yield, and calculated the flowering date from growth stage observations. Landscape parameters (proportion of non‐crop and OSR area, change in OSR area relative to the previous year) were calculated at six spatial scales (0.6–5 km). Pollen beetle abundance increased with MAT but to different degrees depending on the landscape context, that is, increased less strongly when OSR proportions were high (1‐km scale), interannually constant (5‐km scale) or both. In contrast, stem weevil abundance and stem damage did not respond to landscape composition nor MAT. Pollen beetle larval parasitism was overall low, but occasionally exceeded 30% under both low and high MAT and with reduced OSR area (0.6‐km scale). Despite high pollen beetle abundance in warm climates, yields were high when OSR flowered early. Thereby, higher temperatures favoured early flowering. Only among late‐flowering OSR crop fields yield was higher in cooler than warmer climates. Bud loss responded analogously. Landscape composition did not substantially affect bud loss and yield. Synthesis and applications: Earlier flowering of winter OSR compensates for higher pollen beetle abundance in warmer climates, while interannual continuity of OSR area prevents high pollen beetle abundance in the first place. Thus, regional coordination of crop rotation and crop management promoting early flowering may contribute to sustainable pest management in OSR under current and future climatic conditions.

Implications of using fermentation plant extract formulations against pests and predator in rice plants

Currently the use of plant extracts to reduce pest attacks is a concern. Mixed formulation of two plant extracts Calatropis gigantea and Crescentia cujete was applied in the filed rice to assess the effectiveness of these formulations in reducing insect pest populations and predatory (natural enemies). The results showed that the combination of C. gigantea and C. cujete in one formulation could reduce the population of the main pests of rice plants and did not affect the presence of natural enemies (predators). The field trials showed that mixing C. gigante and C. cujete in liquid formulation reduced pest population compared the farmer with treatment synthetic pesticide. Population decrease of scipophaga innotata with range 21-77 percent, Cnaphalocrosis medinalis 25-79 percent. The abundance of pests was very low when using the plant extract formulation, whilst the synthetic pesticide generally had a higher number of pests. Predator numbers were higher in plant extract formulation and low with synthetic insecticide by farmer application. Synthetic insecticides have a very large impact on predators while plant extract formulations have no impact because the predator population is still higher than application by synthetic. Plant extract formulation (mixed C. gigantean and C. cujete) is more effective in reducing population pests than synthetic pesticides. The plant growth parameters were better in the treatment of plant extracts formulation than the application by farmer. This research indicated that using plant extracts formulation effective to control pests can be as effective compared as synthetic insecticides by using of farmer.