Numbers Of Beneficial Insects Research Articles

Aberrant splicing of a nicotinic acetylcholine receptor alpha 6 subunit is associated with spinosad tolerance in the thrips predator Orius laevigatus

Susceptibility to insecticides is one of the limiting factors preventing wider adoption of natural enemies to control insect pest populations. Identification and selective breeding of insecticide tolerant strains of commercially used biological control agents (BCAs) is one of the approaches to overcome this constraint. Although a number of beneficial insects have been selected for increased tolerance to insecticides the molecular mechanisms underpinning these shifts in tolerance are not well characterised. Here we investigated the molecular mechanisms of enhanced tolerance of a lab selected strain of Orius laevigatus (Fieber) to the commonly used biopesticide spinosad. Transcriptomic analysis showed that spinosad tolerance is not a result of overexpressed detoxification genes. Molecular analysis of the target site for spinosyns, the nicotinic acetylcholine receptor (nAChR), revealed increased expression of truncated transcripts of the nAChR α6 subunit in the spinosad selected strain, a mechanism of resistance which was described previously in insect pest species. Collectively, our results demonstrate the mechanisms by which some beneficial biological control agents can evolve insecticide tolerance and will inform the development and deployment of insecticide-tolerant natural enemies in integrated pest management strategies.

Biological method of plant protection is one of the green economy development directions

The importance of the biological method of plant protection as one of the prospects for the green economic development in Russia and in the world is discussed in the article. The modern directions of the Russian agricultural science development for the transition to environmentally friendly agricultural production are analyzed. The experience of biological preparations and biological agent’s application in Russia and abroad is considered in the historical aspect. A differentiated approach has been proposed for chemical treatments prescribing, carrying them out only in pest proliferation centers, on border land and catching band, which makes it possible to almost halve the pesticides use. The field research results on the study of the spatial distribution of useful entomofauna in irrigated agricultural landscapes are presented, ways of increasing the species diversity and number of beneficial insects (entomophages and parasites) in agrocoenosis due to the redistribution of useful entomocomplex species in agrocoenosis and natural agricultural landscape are shown.

Measuring the effect of non-crop flowering plants on natural enemies in organic tobacco

The use of “insectary strips” of sunflowers and buckwheat is widely promoted by organic certifiers to promote control of the green peach aphid (Myzus persicae) and other pests in organic tobacco. However, no published research supports this recommendation in tobacco, and results from other crops are mixed. We performed a series of experiments to test the effects of non-crop plantings of sunflowers and buckwheat on key pest and beneficial insects adjacent to organic tobacco fields in North Carolina. Although some reduction in M. persicae infestations and increases in numbers of beneficial insects were observed on tobacco plants near field-edge insectary treatments, these effects were small and were observed only over a short distance into the crop. Planting additional insectary strips in the field interior did not reduce aphid numbers in comparison to control treatments and led to increases in some pest insects. These conservation biological control techniques are unlikely to be a reliable method of controlling M. persicae and other pest insects in organic tobacco.

Effect of intercropping carrot (Daucus carota L.) with two aromatic plants, coriander (Coriandrum sativum L.) and summer savory (Satureja hortensis L.), on the population density of select carrot pests

Abstract Intercropping, or the use of different aspects of the interaction between organisms in ecosystems, can be classified as an ecological method that limits harmful human interference in the environment, especially the consumption of chemicals. The impact of intercropping carrot with coriander Coriandrum sativum L. and summer savory Satureja hortensis L. on the occurrence of select carrot pests was estimated in the years 2010-2011. Intercropping had a significant effect on the decrease of the number of roots damaged by carrot rust fly Psila rosae. During harvest, the least number of damaged roots was observed in combination with summer savory S. hortensis L. The number of carrot psyllid Trioza viridula Zett. and aphids on carrot leaves and roots damaged by nematodes was significantly lower on plots where carrot was intercropped. Intercropping both herbs had a positive influence on the number of beneficial insects. In all of the years of the study, the highest number of Coccinellidae and Syrphidae were observed on plots where carrot was intercropped with coriander.

Health and environmental impacts of pesticide use practices: a case study of farmers in Ekiti State, Nigeria

Commonly used pesticides and handling practices which might expose farmers and their environment to chemical hazards were investigated in the Irepodun/Ifelodun local government area of Ekiti State, Nigeria. Direct field observations and answers to a structured questionnaire from a random sample of 150 farming households showed that commonly used pesticides comprised herbicides (48.3 per cent), fungicides (28.2 per cent) and insecticides (23.5 per cent). Of these, 86.7 per cent are classified as ‘highly’ hazardous by the World Health Organization (WHO) and have been banned or restricted in many developed countries. Nearly all of the farmers (94.7 per cent) had received no formal training in safe pesticide use and mixed different products. Farmers suffered from discomforts ranging from eye irritation (91.3 per cent), skin problems (87.3 per cent), nausea (86.0 per cent), headache (83.3 per cent) and vomiting (58.0 per cent). More than half of the pesticide applicators (61.3 per cent) sprayed pesticides near water bodies. Only a few farmers reported decreasing trends in numbers of beneficial insects (27.3 per cent) and other animals (29.3 per cent). The results showed that the awareness of farmers and authorities needs to be raised regarding the use of protective equipment and correct procedures when handling pesticides and, also, that there should be stricter enforcement of existing pesticide regulation and monitoring policies to minimize the threats that the farmers' current practices pose to their health and to the environment.

ARMYWORM, STINK BUG AND LEAFMINER CONTROL ON FRESH MARKET TOMATOES, SPRING 2006

Transplants were set 21 Mar, 18 inches apart within the row on 8-inch-high and 32-inch-wide beds of Myakka fine sand covered with white polyethylene mulch. Each plot consisted of a single 18-ft long row with rows spaced 5 ft apart and 7 ft end to end. Treatments were replicated four times in a randomized complete block design and were applied with a 2.5 gal, hand-held CO2-powered sprayer at 60 gpa on 25 Apr, 10 and 23 May, and at 90 gpa on 6 Jun (Table 1). The sprayer was fitted with a D-5 disk and #45 core and was operated at 60 psi. The number of Liriomyza trifolii leafmines ≥ 0.5 inch long were counted on 25 May and 8 Jun during a 1 min search of each plot by two individuals, and the numbers were totaled for analysis. On 10 May, the middle 10 plants of selected plots were shook and the numbers of beneficial insects dislodged were counted. Fruit were harvested on 31 May and 21 Jun from the middle 10 plants of each plot and the number and weight of non-damaged fruit and the number of fruit damaged by armyworm larvae and stink bugs were determined.

Nontarget Impact of Spinosad GF-120 Bait Sprays for Control of the Mexican Fruit Fly (Diptera: Tephritidae) in Texas Citrus

Bait sprays containing the toxicant spinosad (GF-120) were applied to citrus groves in the Rio Grande Valley of Texas where Mexican fruit flies were detected in surveillance traps. The sprays were applied as a supplement to a continuous sterile insect release program. Sterile fly captures were 47-63% lower in the treated groves compared with control groves. Eight of 10 secondary pest populations declined in the test groves subsequent to spray applications, but they also declined in the control groves, suggesting that the decline was a seasonal phenomenon rather than a result of the bait sprays. Citrus whitefly, Dialeurodes citri (Ashmead), populations increased modestly and citrus blackfly, Aleurocanthus woglumi (Ashby), populations remained unchanged compared with pretreatment levels. Thus, no outbreaks of secondary pests occurred as a result of the spinosad bait sprays in this instance, as has been reported for malathion bait sprays in citrus. The bait sprays had no detectable effect on populations of specific indicator species of parasitoids (including Aphytis spp. and Comperiella bifasciata Howard), or on numbers of beneficial insects in general, in the treated groves.

Suppression of pink bollworm and effect on beneficial insects of a nectariless okra-leaf cotton germplasm line

AbstractInfestations of pink bollworm, Pectinophora gossypiella (Saunders), (Lepidoptera: Gelechiidae), and numbers of beneficial insects in two cottons, Gossypium hirsutum, were compared at Maricopa, Arizona, and Brawley, California, during the 1986–1988 seasons. Plots (0.8 ha) of WC-12NL (nectariless, okraleaf, and early maturing) had significantly lower boll infestations than DPL-61 (nectaried, normal leaf, and later maturing) for each location and year. The three year average (range) PBW/100 bolls for WC-12NL and DPL-61 at Maricopa were 6.8 (5.7–10.7) compared to 11.2 (6.8–15.7), respectively. At Brawley the averages were 18.9 (9.3–27.6) compared to 39.2 (15.5–52.5), respectively. With the exception of 1986 at Maricopa, the percentage of bolls with eggs was significantly greater for DPL-61 (average 8.1, range 3.4–16.0) than for WC-12NL (average 4.2, range 1.1–12.1) for each location and year. Both cottons averaged about four eggs per oviposited boll; not significantly different. The numbers of Lygus spp. and three beneficial species of insects were not different in the two cottons. Collops vittatus (Say) (Coleoptera: Melyridae) was collected in significantly greater numbers in WC-12NL (1.0 per 50 sweeps compared to 0.9 for DPL-61), while Hippodamia convergens (Guérin-Ménéville) (Coleoptera: Coccinellidae) was collected in greater numbers in DPL-61 (0.6 per 50 sweeps compared to 0.3 for WC-12NL). WC-12NL is the culmination of a 20-year breeding programme for resistance to P. gossypiella and has characteristics attractive for cotton production in areas where a shorter growing season is desirable.

Observations on Population Levels of the European Red Mite (Acarina: Tetranychidae) and Associated Arthropod Predator Complexes in Different Spray Programs Over a 5-Year Period

Selective and nonselective insecticide and fungicide treatments were applied in season-long programs in a Swiss apple orchard, for the control of arthropod and fungal pest complexes. The effects of these treatments on the European red mite, Panonychus ulmi (Koch), and its predators were studied over a period of 5 years. Abroad-spectrum compound, azinphos-methyl, gave good control of the codling moth, Cydia pomonella L., under a program of four to six sprays every 2 weeks per season. Equal or slightly inferior control was given by the more selective chemicals, chlordimeform and diflubenzuron. Fungicides used were either mite-suppressive or had no effect on mite predators. Effective P. ulmi predation was also enhanced by the use of selective acaricides and the combined effects of a predaceous mite, Amblyseius finlandicus (Oudemans), and a number of beneficial insects which became established in the blocks that received the selective insecticide treatments. These beneficial arthropods kept P. ulmi numbers below the damage threshold, demonstrating that integrated chemical and biological control of this pest is possible.

Strip-Cropping's Effect on Beneficial Insects and Spiders Associated with Cotton in Oklahoma 2

Larger numbers of beneficial insects were found in cotton growing immediately adjacent to sorghum, rows 1-12, than in cotton grown distal to this strip-crop, rows 13-24. The cotton-corn association exhibited the reverse effect. Lady beetles, Hippodamia spp., were one of the main predators, with significantly more individuals being found in cotton adjacent to sorghum than in the cotton associated with corn. As the season progressed, the level of beneficial organisms declined, except for the occurrence of lady beetles. Lady beetles exhibited the only significant increase in population during the late-season bollworm, Heliothis zea (Boddie), increase. Parasitism varied throughout the season and averaged 26.3%. Sorghum proved to be the best associate crop because of its effect on beneficial organisms and its ability to provide a marketable crop in southwest Oklahoma.