Beneficial Arthropod Populations Research Articles

Use of Locally Food Attractants for Ceratitis capitata (Diptera: Tephritidae)

The high price of commercial products against pests impose small farmers to use a locally available baits against C.capitata that is the most fruit fly in our country. The aim of this research was to evaluate the effectiveness of food-based attractants for the capture of C. capitata as well as their selectivity on the populations of beneficial arthropods. we tested some local fermentation products compared to commercial lures (CeraTrap®). Four attractants were evaluated in two peach orchads. Field evaluations show that local fermentation products, particularly the red wine solution outperformed other food-based attractants. However, the average of fruit damage was differed between the four attractants and it was high in the border than in the center of each attractants plot. These attractants also were selective, capturing few beneficial arthropods. It will be necessary to focus our research on how to optimally employ such a trap in conjunction or alternative with other control techniques to drive concerted and integrated pest management due to its low environmental impacts and selectivity toward beneficial insects.

Exploring multifunctionality of summer cover crops for organic vegetable farms in the Upper Midwest

AbstractIntensive vegetable crop rotations can have detrimental effects on soil health, draining soil of organic matter reserves and necessitating nitrogen (N) inputs. In addition, many vegetable crop rotations leave little time or space to integrate beneficial arthropod and pollinator habitat into crop rotations; the lack of habitat may cause declines in beneficial arthropods, which can lead to insufficient pollination services and increased pest pressure. Nine treatments, each containing one to seven species of cover crops, were evaluated for flowering, aboveground biomass production and N content, soil${\rm NO}_3^-$-N contribution after biomass incorporation, and beneficial arthropod visitation. A seven-species mix composed of oat (Avena sativaL.), field pea (Pisum sativumsubsp.ArvenseL.) and five clover species (Trifoliumspp.) added the largest amount of biomass (8747 kg ha−1). Likewise, this mix contributed the most organic N (265.6 kg N ha−1), and increased soil${\rm NO}_3^-$-N after biomass incorporation (10.9 mg${\rm NO}_3^-$-N kg−1of soil). Buckwheat (Fagopyrum esculentumMoench) and phacelia (Phacelia tanacetifoliaBendth.) monoculture produced most abundant floral resources. Beneficial arthropods observed included pollinators (native, honey and bumblebees), predators (syrphid flies and green lacewings) and parasitoids. Increased floral diversity was associated with abundance of flies in the Syrphidae family. Phacelia monoculture was most attractive for bees in the Apidae and Halictidae family, both of which may provide pollination services. These results highlight floral visitation patterns as an indicator for beneficial insect community support and conservation, especially in summer months, when greater insect reproduction occurs. Summer-planted cover crops are an underexplored rotation option for organic farming systems in the Upper Midwest, and may provide a wide range of ecosystem services including increases in available soil N and beneficial arthropod populations.

Sweep netting samples, but not sticky trap samples, indicate beneficial arthropod abundance is negatively associated with landscape wide insecticide use

Abstract Insecticide use and landscape context are major drivers for the abundance of beneficial arthropods, such as predators, parasitoids and pollinators. However, the relative importance of local and landscape‐wide insecticide use is not well understood, and it is unclear to what extent impacts of insecticides on beneficial arthropod populations are moderated by landscape composition. We collected and analysed data on beneficial arthropod abundance and local and landscape‐wide insecticide use across 38 Dutch landscapes. We used regression to study the associations between beneficial arthropod abundance (response), insecticide use and landscape factors. Insects were sampled by sweep netting and yellow sticky traps in field margins (‘sampling sites’) in the summer of 2017 and 2018. We paired organic and conventional sites in the same landscape setting. We used three indicators of insecticide use: management (organic vs. conventional), Treatment Frequency Index of insecticides applied in the field adjacent to the sampling site, and the estimated landscape‐wide average quantity of insecticides applied per ha within a 1 km radius around the sampling site. Abundances of beneficial arthropods in field margins, assessed by sweep netting, were negatively associated with the estimated quantity insecticide applied in the surrounding landscape, while arthropod sampling by sticky traps did not show this relationship. Pollinator abundance was negatively associated with conventional management and with the frequency of insecticide applications in the adjacent field, while predator and parasitoid abundance did not show significant associations with local insecticide use indicators. Negative impacts of insecticide use were not moderated in more diverse landscapes with higher proportions of semi‐natural habitats. Policy implications. Insecticide impacts on arthropod populations extend beyond the fields in which they are used. Awareness of the potential landscape‐wide effects of pesticides, either through drift of pesticides or insect movement, may encourage land managers to adopt practices to reduce insecticide drift and the frequency of insecticide applications, thereby reducing the impacts of landscape‐wide exposure on arthropods that provide services to agriculture. Risk assessments of insecticides and pesticide use regulations need to account for potential spill‐over effects and consider landscape‐scale consequences associated with the source–sink dynamics of arthropods.

Love thy neighbors? Beneficial and pest arthropod populations in a pear and cherry orchard landscape

Neighboring vegetation in an agricultural landscape can impact pest and beneficial arthropod populations in tree fruit orchards. In a pear monocrop region (such as Wenatchee WA, northwestern United States), the concern is that specialist pests can migrate from orchard to orchard and maintain an area-wide high population. In a mixed landscape region (such as Hood River OR, NW USA), the concern is that chemical control measures against invasive pests in nearby cherry orchards can disrupt biological control in pear orchards by killing beneficial arthropods. Specifically, we asked whether surrounding pear and cherry area cover (% in 1 km2), presence of adjacent cherry orchards, and pesticide impact scores influenced the abundance and richness of common pests (pear psylla and two-spotted spider TSS mites) and beneficial arthropods (the parasitoid wasp Trechnites insidiosus and generalist predators) in pear orchards in OR and WA. Pests and beneficial arthropods were collected in pear plots in OR and WA in 2016–2018 using a combination of methods (sticky cards, beat trays, leaf samples). A generalized linear mixed model revealed that surrounding pear cover area did not affect any of the outcome variables. Surrounding cherry cover had variable effects on pest and beneficial abundance in different regions and years, such as a negative correlation with predator abundance (OR 2016), a positive correlation with parasitoid abundance (WA 2017), and higher pear psylla abundance in cherry-adjacent pear plots (OR 2018). Furthermore, a quantile regression showed that pear orchards with low surrounding cherry cover had high variance in parasitoid abundance, while pear orchards with high surrounding cherry cover had consistently low parasitoid abundance. Pesticide impact scores negatively influenced predator and parasitoid abundance and beneficial richness in WA, but not in OR. Pear plots with higher pesticide impact scores had higher TSS mite abundance (in both OR and WA 2018), but did not affect pear psylla abundance. A redundancy analysis (RDA) showed that beneficial population assemblages tended to cluster away from pear plots with high pesticide impact scores. This study shows how landscape and chemical control practices can have variable impacts on pear orchards located in different regions.

Does Cover Crop Management Affect Arthropods in the Subsequent Corn and Soybean Crops in the United States? A Systematic Review

Abstract Cover crops (CC) support populations of pest and beneficial arthropods. The status of these arthropods in the subsequent cash crop depends on several factors such as CC species, management, biomass production, and weather conditions. A systematic review was performed to identify how CC management influences pest and beneficial arthropods and to identify knowledge gaps for the future research efforts. Eight studies included in this review indicated that CC increase beneficial arthropods or some beneficial arthropods compared with the CC managed fields. A minority of the studies indicated an increase in pest presence when using CC. Cover crop species, termination time and methods, and CC management had variable responses on arthropod activity-density. The variable responses, differences on study designs, and complexity of CC management influence arthropod activity in a CC-corn [Zea mays L. (Poaceae)]/soybean [Glycine max L. (Fabaceae)] system, limiting our ability to draw a broad and effective conclusion about the CC management impact on arthropods. Local research studies are needed to identify the impact of CC biomass quality and quantity, CC biomass thresholds for pest and beneficial arthropods, and cash crop yield impact of CC management-arthropod-related studies. Studies using the standard farming practices of each U.S. region and using standard measurements are needed to guide farmers that use cover crops. This systematic review aims to provide a better understanding of how the complexity of management in cover crop-corn/soybean management affects arthropod activity-density and to identify potential gaps in research and address future research needs.

Abundance and diversity of arthropods in transgenic Bt and non-Bt cotton fields under Indian conditions

Two-year field studies during Kharif 2015 and 2016 were conducted to assess the abundance and diversity of arthropod communities of Bt cotton carrying Cry1Ac and Cry2Ab proteins and non-Bt cotton under sprayed and unsprayed conditions. The experiment was conducted in a randomized block design with four treatments of BG-II and non-Bt cotton. The treatments were non- transgenic cotton with no insecticide treatment, non-transgenic cotton with insecticide treatment, transgenic cotton with no insecticide treatment and transgenic cotton with an insecticide treatment. Arthropod community categorized as target insect pests, sucking insect pests, natural enemies and non-target insects were recorded at different phases of the cotton crop. The sucking insect pests contributed the highest abundance among the total arthropods recorded during the period of study. The abundance and diversity of bollworms that were recorded from non-Bt cotton only suggested effectiveness of BG II cotton against target insect pests. The abundance, species richness and diversity indices with respect to populations of beneficial predaceous arthropods and non-target insects were similar in BG-II and its non-Bt counterpart under unsprayed conditions. On the contrary, these parameters were significantly on the lower side under sprayed regimes for both genotypes. The spray of insecticides in early season against sucking insect pests significantly reduced their abundance and diversity indices in both BGII and non-Bt cotton. As monocropping of BG-II cotton is common on large parts of India, there is a need to monitor the populations of non-target insect species with special emphasis on sucking insect pests on a continuous basis to understand the long-term impact of Bt crops on insect biodiversity for sustainable integrated pest management practices.

Effect of pan trap size on the diversity of sampled bees and abundance of bycatch

Monitoring pollinator health and pollination is among the top priorities to safeguard pollinators and secure pollinator services. Assessments of sampling methods are therefore essential for developing a standardized protocol for long-term pollinator monitoring. Pan trapping is a popular technique to survey pollinators, but limited information is available on the effect of pan trap diameter on the abundance, richness, and body size of sampled bees, as well as on the abundance of bycatch (non-targeted arthropods). We conducted experiments using four diameters of yellow pan traps in three habitats (a semi-natural phrygana habitat, a roadside, and a salt flat) on the Greek island of Lesvos during a 10-day period in late June/early July of 2017 and 2018. We found that pan traps of 4, 7, 10, and 12 cm captured a similar richness of bees and have little or no effect on the abundance estimates of bees and flies. Pan trap diameter did not affect body size of collected bees. Bycatch accounted for 62.8% of the arthropods collected and increased with the diameter of the pan traps in the phrygana and roadside habitats. According to literature, many researchers, especially outside Europe, use pan traps of various diameters (7–34 cm), volumes (96.1–2000 ml), and shapes (round, square, rectangular, or hexagonal). To reduce potential negative effects on populations of other beneficial arthropods, as well as to minimize processing effort and costs, we recommend using small pan traps (7 cm), unless standardized pan trapping protocols have already been adopted.

A high-diversity/IPM cropping system fosters beneficial arthropod populations, limits invertebrate pests, and produces competitive maize yields

In the United States, current crop production often favors simplified rotations of maize and soybeans in conjunction with a heavy reliance on synthetic inputs that consequently degrade environmental health and increase production costs, without necessarily improving yields. While often stigmatized as underperforming compared to conventional systems, “sustainable intensification” of cropping systems offers an alternative that relies on crop rotation diversity, continuous crop cover, and integrated pest management to combat pests. Within a long-term no-till systems experiment, our main goal was to determine if a high diversity-IPM system (HiDiv-IPM) could compete with a low diversity-preemptive pest management system (LoDiv-PP) in terms of invertebrate pest management, biological control, and maize establishment and yield. Our results suggest that early-season pests, particularly caterpillars, reduced maize establishment by 10 % in the HiDiv-IPM system compared to the LoDiv-PP system. Both our simple and more diverse rotations suffered from slug damage that reduced crop establishment, however, overall slug abundance and damage tended to be equal. Despite lower seedling establishment and greater caterpillar damage, maize in the HiDiv-IPM rotation yielded similarly to the LoDiv-PP rotation, suggesting that other factors, such as higher levels of predation evident in the more diverse rotation or possible nutrient- and soil quality-related issues, contributed to productivity. These results support the notion that a HiDiv-IPM system can compete with a LoDiv-PP system and, contrary to the most common approach for controlling insects in maize production in the U.S., aggressive, preemptive pest management was not necessary to achieve competitive yields.

Wildflower plantings harbor increased arthropod richness and abundance within agricultural areas in Florida (USA)

AbstractIntensive agriculture has led to a reduction of overall biodiversity and ecosystem services such as pollination and biological control. To offset these economic losses, many farmers are planting native wildflowers to enhance flowering plant diversity and augment pollinator and other beneficial arthropod populations on their farms. In this study, we examined arthropod communities in Florida (USA) within wildflower plots and fallow control plots, which were primarily composed of grasses. Significantly more herbivorous insects, predatory arthropods, and pollinators were found within wildflower plots than in fallow control plots. We also implemented pollinator surveys at flowering plants. These surveys highlighted numerous plant–pollinator interactions within wildflower plots, supporting the idea that some native wildflower species are more attractive to pollinators than are others. Nevertheless, utilizing diverse flowering plants for wildflower plots may support a wide diversity of beneficial arthropod species, including native bees. Our results suggest that wildflower plantings in Florida can be a successful management tool to harbor increased overall plant and arthropod diversity (including native pollinators and other beneficial arthropods) within intensive agricultural areas.

The Contribution of Surrounding Margins in the Promotion of Natural Enemies in Mediterranean Apple Orchards.

(1) Habitat management can enhance beneficial arthropod populations and provide ecosystem services such as biological control. However, the implementation of ecological infrastructures inside orchards has a number of practical limitations. Therefore, planting/growing insectary plants in the margins of orchards should be considered as an alternative approach. (2) Here, we assessed the efficacy of a flower margin composed by four insectary plant species (Achillea millefolium, Lobularia maritima, Moricandia arvensis and Sinapis alba), which was placed on an edge of four Mediterranean apple orchards to attract natural enemies of two apple tree aphids (Dysaphis plantaginea and Eriosoma lanigerum). We also characterized the natural enemies present in the aphid colonies. (3) Our results show that the implementation of a flower margin at the edge of apple orchards attracts predators (Syrphidae, Thysanoptera, Araneae, Heteroptera, Coleoptera) and parasitoids. Parasitoids are the main natural enemies present in aphid colonies in our area. (4) The implementation of the flower margins successfully recruited natural enemy populations, and the presence of parasitoids in the surroundings of the orchards increased the parasitism of D. plantaginea colonies.

Development and Survival of Lygus hesperus (Hemiptera: Miridae) Nymphs Under Constant and Variable Temperatures.

Thermal environments of the arid western United States are often harsh compared with the ranges of temperatures favorable for development and survival of crop insect pests. In cotton [Gossypium spp. (Malvales: Malvaceae)], new irrigation practices such as deficit irrigation may impact populations of pest and beneficial arthropods by temporarily altering temperature profiles within the plant canopy. Most information regarding the temperature-dependent development and survival of an important cotton pest, the western tarnished plant bug (Lygus hesperus Knight), is derived from constant temperature studies. We examined the development and survival of L. hesperus nymphs under constant (±0.2°C) and variable (±8°C) temperature regimes at daily mean temperatures of 15, 22, and 29°C. Under the low temperature (15°C), stadium lengths and duration of the nymphal stage were shorter when temperatures were variable compared with a constant temperature. No differences in development times were observed between regimes at the medium temperature (22°C). Except for the first stadium, development times under the high variable temperature regime were longer compared with the high constant regime (29°C). Nymph survival was unaffected by temperature regime except at the lowest temperature, where daily thermal fluctuations substantially improved survival compared with the constant conditions. These results suggest that temporarily increased crop canopy temperatures caused by altered irrigation schemes are unlikely to substantially reduce the growth of L. hesperus populations. However, enhanced nymphal development and survival under low variable temperatures likely contribute to the survival of overwintering L. hesperus in the absence of acute, low-temperature mortality.

Remotely Estimating Beneficial Arthropod Populations: Implications of a Low-Cost Small Unmanned Aerial System

Studies show that agricultural land requires investment in the habitat management of non-cropped areas to support healthy beneficial arthropods and the ecosystem services they provide. In a previous small plot study, we manually counted blooms over the season, and found that plots providing greater numbers of flowers supported significantly higher pollinator populations over that of spontaneous weed plots. Here, we examined the potential of deploying an inexpensive small unmanned aerial vehicle (UAV) as a tool to remotely estimate floral resources and corresponding pollinator populations. Data were collected from previously established native wildflower plots in 19 locations on the University of Georgia experimental farms in South Georgia, USA. A UAV equipped with a lightweight digital camera was deployed to capture images of the flowers during the months of June and September 2017. Supervised image classification using a geographic information system (GIS) was carried out on the acquired images, and classified images were used to evaluate the floral area. The floral area obtained from the images positively correlated with the floral counts gathered from the quadrat samples. Furthermore, the floral area derived from imagery significantly predicted pollinator populations, with a positive correlation indicating that plots with greater area of blooming flowers contained higher numbers of pollinators.

Beauty with benefits: butterfly conservation in Washington State, USA, wine grape vineyards

The butterfly fauna of south central Washington State, USA is characterized by shrub-steppe specialists adapted to hot, dry summers and cold winters. However, the shrub-steppe ecosystem has diminished at an alarming rate due to extensive agricultural development fostered by access to an abundant water supply from the Cascade Mountains. This has resulted in loss and fragmentation of habitat for ~50 species of butterflies which are now in decline. Viticulture is a major agricultural industry in south central Washington and has transitioned in recent years to a sustainable, low pesticide-input enterprise. Current viticultural pest management research is focused on restoration of shrub-steppe habitat and native plants to enhance and sustain beneficial arthropod populations (predators and parasitoids) for pest control. Butterfly populations were surveyed during 2012–13 in a pair of vineyards (habitat-enhanced, conventional) in each of four viticultural regions [Columbia gorge (CG), Walla Walla valley (WWV), Yakima valley (YV), Wahluke slope (WS)] in south-central Washington. The habitat-enhanced sites supported a significantly greater number of flowering plant species (mostly native) than conventional vineyard sites. Twenty nine butterfly species were recorded from the habitat-enhanced vineyards with only nine of these recorded from the conventional vineyards. Overall, there were double the number of species in habitat-enhanced vineyards [mean (±SE) 5.62 ± 0.85] compared to conventional vineyards (2.75 ± 0.75) although this was not statistically significant. A significantly greater number of species occurred in the CG and WWV habitat-enhanced vineyards (10.5 ± 0.5) compared to the conventional vineyards (3.5 ± 0.0) in these regions. Smaller numbers of butterfly species occurred in YV and WS vineyards with no significant differences between habitat-enhanced and conventional sites. Butterfly abundance was significantly greater in habitat-enhanced vineyards (20.37 ± 5.34 individuals/visit) compared to conventional vineyards (5.5 ± 0.9) with greatest differences in the CG and WWV vineyards. The pest management strategy of restoring native plants and habitats in a low pesticide-input crop like wine grapes in central Washington may have substantial benefits for butterfly abundance, diversity and conservation. Many of the flowering native perennials important in attracting and sustaining endemic biological control agents, are also larval hosts and/or nectar sources for threatened shrub-steppe butterflies.

Reusing Plastic Mulch for a Second Strawberry Crop: Effects on Arthropod Pests, Weeds, Diseases and Strawberry Yields

Florida is the second largest producer of fresh-market strawberries (Fragaria × ananassa Duchesne; Rosales: Rosaceae) in the United States. The annual hill “plasticulture” production system used to grow strawberries makes this crop one of the most expensive to produce. The cost of production may be reduced if synthetic mulch can be reused and the dead plants (thatch) from the previous season left in the field, without negatively affecting crop yields. Field studies were conducted during the 2010/2011 and 2011/2012 strawberry growing seasons to evaluate the effect of re-using plastic mulch with or without dead strawberry plants from the previous season on arthropod populations, disease incidence, weeds and strawberry growth, and marketable yields of strawberries. The study was conducted in a commercial field in Citrus County, Florida using 2-yr old synthetic mulch on the bed. Two strawberry varieties ‘Albion’ and ‘Florida Festival’ were planted in 2010/2011 and 2011/2012 growing seasons, respectively. During transplanting, one treatment had all strawberry thatch (dead plant debris from previous season) removed from the soil before planting the new strawberry transplants, while in the second treatment the thatch was left to grow with the transplants. Data were collected throughout the growing seasons on plant growth, spider mites and insect pest populations, weeds, disease incidence, and marketable yield of strawberries. Re-using plastic mulch with or without strawberry thatch had no significant effect on plant size or populations of beneficial and pestiferous arthropods. However, re-using mulch with strawberry thatch reduced weed growth but increased the incidence of fungal diseases. As a result of fungal diseases and plant mortality, marketable yield for the variety “Florida Festival”, but not “Albion” was significantly lower in plots with the strawberry thatch than in those without thatch.

Biology, Ecology, and Management of Brown Marmorated Stink Bug (Hemiptera: Pentatomidae)

Brown marmorated stink bug, Halyomorpha halys Stal, is an invasive, herbivorous insect species that was accidentally introduced to the United States from Asia. First discovered in Allentown, PA, in 1996, H. halys has now been reported from at least 40 states in the United States. Additional invasions have been detected in Canada, Switzerland, France, Germany, Italy, and Lichtenstein, suggesting this invasive species could emerge as a cosmopolitan pest species. In its native range, H. halys is classified as an outbreak pest; however, in North America, H. halys has become a major agricultural pest across a wide range of commodities. H. halys is a generalist herbivore, capable of consuming >100 different species of host plants, often resulting in substantial economic damage; its feeding damage resulted in US$37 million of losses in apple in 2010, but this stink bug species also attacks other fruit, vegetable, field crop, and ornamental plant species. H. halys has disrupted integrated pest management programs for multiple cropping systems. Pesticide applications, including broad-spectrum insecticides, have increased in response to H. halys infestations, potentially negatively influencing populations of beneficial arthropods and increasing secondary pest outbreaks. H. halys is also challenging because it affects homeowners as a nuisance pest; the bug tends to overwinter in homes and outbuildings. Although more research is required to better understand the ecology and biology of H. halys , we present its life history, host plant damage, and the management options available for this invasive pest species.

Alternative Organic Fungicides for Apple Scab Management and Their Non-target Effects

A major challenge in organic apple production in humid production regions is the available fungicide options for apple scab [Venturia inaequalis (Cooke) Wint.] management. The standard sulfur/lime sulfur fungicide program can be injurious to the applicator, the apple ecosystem, and the apple tree itself. The objectives of this study were to compare the efficacy of three potential alternative fungicides [potassium bicarbonate (PB), neem oil (NO), and Bacillus subtilis (Bs)] with a standard organic sulfur/lime sulfur (SLS) fungicide program and a non-treated control (NTC) for management of apple scab and to evaluate potential non-target impacts on pest and beneficial arthropod populations. The five treatments were applied to ‘Empire’ trees arranged in a completely randomized design with five single-tree replications at the University of Vermont Horticultural Research Center in South Burlington, VT. Fungicides were applied with a handgun to drip using maximum label rates. Applications began on 26 Apr. 2007 and 23 Apr. 2008 and continued on approximately a weekly schedule through the end of June and then every 2 weeks through 23 July 2007 and 17 July 2008, respectively. The standard SLS treatment resulted in the best scab control in both years. The NO treatment reduced foliar and fruit scab compared with the NTC and the other alternatives at the end of the 2008 growing season and had insecticidal activity. However, both the SLS and NO treatments had disadvantages, including phytotoxic burning on the fruit and/or significantly more russeting on the fruit at harvest. In each year of the study, one or more of the alternative treatments, particularly Bs, resulted in higher insect damage than the non-fungicide-treated control. This research showed that PB, Bs, and NO do not offer advantages over the standard SLS fungicide program in organic apple production and in some cases offer distinct disadvantages in terms of non-target impacts. Chemical names used: potassium bicarbonate (Armicarb “O”), Bacillus subtilis (Serenade MAX), neem oil (Trilogy), sulfur (Microthiol Sulfur)/lime sulfur (Miller Lime Sulfur)

PEACH APHID MANAGEMENT IN ORGANIC AND CONVENTIONAL ORCHARDS: HOW TO RECONNECT EFFICIENCY AND ECOLOGY?

Considering the various negative side effects of intensive chemical pest control practices, a fundamental shift towards alternative approaches for crop protection is at stake in the agricultural sphere. The control of peach tree aphids requires regular and numerous treatments to achieve protection against direct damage and virus transmission. However, aphid populations are known to be affected by cultural practices and by natural enemies. These are more ecologically sound practices, but their efficiency is questioned. In 2007, we identified and evaluated the protection strategies used on 20 commercial fruit farms (8 organic and 12 conventional farms) in the south of France. We used different data sources: comprehensive interviews, peach orchard protection schedules and monitoring of aphids and beneficial arthropod populations at plot level. A clear distinction between conventional and organic farming appeared. Organic farmers adopted a more integrated management strategy combining alternative and cultural methods rather than only direct control methods. The organic strategy was less efficient than the conventional, which had significantly lower specific infestation indexes. However, the organic strategy promoted diversity and abundance of aphid natural enemies. Efficiency and diversity of these beneficial species appear to be in opposition or are incompatible. However, the redesign of crop protection, and more generally, of the orchard, with regard to the integration of all factors that influence the system, tends to reconnect efficiency and ecology.

IMPACT OF KAOLIN AND BEAUVERIA BASSIANA TREATMENTS AGAINST OLIVE FLY ON THE NON-TARGET ARTHROPODS OF THE OLIVE ECOSYSTEM

The study of biodiversity has received a growing interest from the scientific community. Investigations of the efficacy of compounds allowed in organic farming and their risks for human and environmental health represent an increasingly large body of literature. The aim of this study was to evaluate the environmental impact of two compounds that have potential for registration as organic insect management tools against Bactrocera oleae. Kaolin clay, a repellent, and a micoinsecticide based on the vital spores of Beauveria bassiana were tested in an olive ecosystem. Selected arthropod taxa (Arachnida: Araneae and Opiliones; Hyrraenoptera: Ichneumonidae; other Hymenoptera; Coleoptera: Coccinellidae; Lepidoptera; Neuroptera; Mecoptera and Diptera: Syrphidae) were utilised as bioindicators. Arthropods were collected using yellow sticky traps. The ratio of pest: beneficial arthropods were used to evaluate the sustainability of the agroecosystem. The experimental olive grove was located in Southern Italy, in the middle of Mediterranean Basin. The abundance of Araneae and Hymenoptera was reduced by both treatments, while Lepidoptera were reduced only in the kaolin-treated plots. The ratio of pest: beneficial arthropods were unchanged after treatments. Results demonstrate that both tested products utilised against Bactrocera oleae showed few negative effects on beneficial arthropod populations. The taxon Araneae was identified as the best bioindicator, as these species were able to indicate well-preserved environmental conditions. More investigation on the efficacy of B. bassiana against the olive fly and on its impact on the above ground arthropods is required.

Impact of variable nitrogen fertilisation on arthropods in cotton in Georgia, USA

Reducing fertiliser applications can reduce production costs for cotton ( Gossypium hirsutum L.) growers, as well as nitrogen (N) leaching into the soil and contamination of surface and ground water. But altered N fertilisation may also affect pests and their natural enemies. In this study, plots with four different levels of fertiliser input (0, 45, 90 and 135 kg ha −1 N) were used to investigate the influence of N on cotton pest and beneficial arthropod populations, and on cotton yield in Tifton, GA, USA. We predicted that (1) N fertilisation will correlate positively with cotton plant growth; (2) increased N fertilisation will increase pest populations because plants with more N will be more nutritious for and attractive to herbivores; (3) populations of beneficial arthropods and predation of pests will decline with increased N fertilisation because of reduced plant signaling; (4) increased N fertilisation will increase pest mortality due to parasitoids because of increased host quality. Cotton plant growth was enhanced by N fertilisation but yield was unaffected. N fertilisation significantly affected some pest arthropods but inconsistently. Mirids were most abundant in the high N treatment in 1 year of the study and cotton aphids were most abundant in the highest N treatment in the other year of the study. Arthropod predators were generally more abundant in the high N treatment but only spiders and Geocoris spp. were significantly affected by N treatment, with highest numbers present in the highest N treatment but the significant differences were each only in a single year. The greatest mortality of sentinel pest eggs ( Spodoptera exigua) due to predation occurred under low N conditions. N fertilisation had no significant effects on parasitism of feral or sentinel caterpillars.

Mortality and recovery of eucalypt beetle pest and beneficial arthropod populations after commercial application of the insecticide alpha-cypermethrin

Alpha-cypermethrin is widely used in Australian forestry to control defoliating beetle pests but no information exists on its efficacy against beetle pests or impacts on non-target arthropods. To address this deficiency I quantified the short-term impacts of single commercial applications of the insecticide alpha-cypermethrin on populations of both defoliating beetle pests and beneficial arthropods over 12 months in two southwestern Australian eucalypt plantations. A single application of alpha-cypermethrin (24 g a.i./ha) in October or November reduced beetle pest populations to near zero levels. Beetle recovery began immediately after spraying but high populations of eucalyptus weevil and chrysomelid beetles, and high defoliation levels did not eventuate until 10–12 months later. Despite the success of alpha-cypermethrin in controlling defoliating beetle pests, the broad-spectrum nature of the insecticide led to nearly complete mortality of all beneficial arthropods immediately after spraying. Spiders were the main group of beneficial arthropods present after spraying probably because some individuals occupy a concealed and protected habitat. Populations of Anaphes nitens (Girault), the important eucalyptus weevil egg parasitoid, also partly survived the spray because they were protected within weevil egg masses. Post-spray recovery of both beetle pests and beneficial arthropods occurred gradually in the following 12 months, presumably through immigration from outside the plantation.