Investigation of Thrips tabaci Lind. as a cotton pest and the development of strategies for its control in Punjab

Thrips tabaci Lind. migrates from the lower to the upper portion of the cotton plant as the season progresses and plants increase in size. The population level of thrips on seedlings should be determined by visual observations of leaf damage instead of scouting. The crop should be sprayed before the damage level is such that seedling leaflets have a cup-like appearance. Combined attack by thrips (14.6 per leaf) and jassid (4.6 per leaf) caused a 37.6% loss in the yield of seed cotton. Granule application at the seedling stage and foliar sprays at later stages is suggested as a control strategy. Thrips and jassids appear to be mutually exclusive but the exact mechanism is not known.     

DIVECOSYS: Bringing together researchers to design ecologically-based pest management for small-scale farming systems in West Africa

Crop pests are a major constraint to the intensification of agricultural production in the tropics, with novel issues related to global change (climate, land use, biological invasions, etc.), food security and preservation of natural resources and biodiversity. A research, extension and education network called DIVECOSYS (Diversity of cropping systems and ecologically-based pest management in West Africa) was launched in 2010 to synergize applied research actions in response to growing concerns on the vulnerability of agricultural systems to pest management in West Africa. This scientific network brings together research and academic institutions, with expertise spanning a multidisciplinary perspective from biology and ecology to remote sensing, agronomy and integrated pest management. Its main scientific objective is to explore the potential of biodiversity and ecological processes such as pest regulation, enabling novel ecologically-based models for productive systems, reduction of pesticide use, and adaptation or resilience of farming systems in the face of environmental disruptions. From Northern Senegal to Southern Benin, the research group explores a wide range of ecoregions and socio-ecological contexts, including stakeholders and their objectives, land use and agricultural practices, and management of biodiversity for enhancing biological control. Main challenges to be turned into opportunities include (i) encouraging collaborations amongst researchers from different scientific fields, (ii) fostering interactive research and synergies among research institutions and among countries, and (iii) developing an ecological engineering approach for the design of sustainable agricultural systems for smallholder farmers.     

Evaluation of a virus-insecticide combination for cotton pest control in Togo

A low dose of cypermethrin combined with Mamestra brassicae virus was applied weekly against the bollworms Helicoverpa armigera (Hübner) and Diparopsis watersi (Rothschild) in smallholder cotton plots in northern Togo in 1989 and 1990. The timing of treatments was based on action thresholds. One or two additional sprays of Bacillus thuringiensis were applied to control Syllepte derogata F., or dimethoate to control aphids. No significant yield differences were observed between the plots treated with the pyrethroid-virus combination and the control plots, treated with the recommended insecticide schedule. However, the latter had a significantly higher percentage of healthy bolls. The virus applied was not reisolated from insects collected in the field.     

Current control methods for diamondback moth and other brassica insect pests and the prospects for improved management with lepidopteran-resistant Bt vegetable brassicas in Asia and Africa

The diamondback moth (DBM), Plutella xylostella (L.), remains a major pest of brassica crops worldwide. DBM has been estimated globally to cost US$ 1 billion in direct losses and control costs. Chemical control of this pest remains difficult due to the rapid development of resistance to insecticides and to their effect on natural enemies. These problems are especially severe in South Asia and Africa where lack of knowledge, limited access to newer and safer insecticides, and a favourable climate result in DBM remaining a serious year-round pest which substantially increases the cost and uncertainty of crop production. Despite these problems, application of synthetic insecticides remains overwhelmingly the most common control strategy. Biologically-based efforts to control DBM in Africa and Asia have focused strongly on parasitoid introductions. However, despite the identification and deployment of promising parasitoids in many regions, these efforts have had limited impact, often because farmers continue early-season spraying of broad-spectrum insecticides that are lethal to parasitoids and thus exacerbate DBM outbreaks. A significant driver for this pattern of insecticide use is the presence of aphids and other pests whose appearance initiates inappropriate spraying. Despite often extensive training of producers in farmer field schools, many growers seem loath to discard calendar or prophylactic spraying of insecticides. The introduction of an IPM technology that could replace the use of broad-spectrum insecticides for DBM and other key Lepidoptera is crucial if the benefits of parasitoid introduction are to be fully realised. The deployment of DBM-resistant brassicas expressing proteins from Bacillus thuringiensis could help to break this cycle of insecticide misuse and crop loss, but their deployment should be part of an integrated pest management (IPM) package, which recognises the constraints of farmers while addressing the requirement to control other Lepidoptera, aphids and other secondary pests.     

Factors affecting content and bioefficacy of neem (Azadirachta indica A. Juss.) phytochemicals used in agricultural pest control: A review

Neem-based products including traditional preparations and formulations have been used extensively for the control of insect pests attacking agricultural crops. Content of phytochemicals extracted from different parts of the neem plant varies considerably due to abiotic and biotic factors from collection of the raw material to extract preparation and product formulation. Likewise, effectiveness of crude or synthesized material used in the field or laboratory may be influenced by storage conditions, content of active ingredient (especially azadirachtin), insect species and its growth stage, type of formulation and synergism of products with other control measures. In this paper, the direct and indirect actions of neem phytochemicals on insect pests are described and practical implications for future pest control strategies are discussed.     

Propagation and release of natural enemies for control of cotton insect and mite pests in the United States

The state of the art for controlling four primary pests or pest complexes by augmentative releases of predators and parasitoids in the United States is reviewed. The pests are (1) the bollworm, Helicoverpa zea (Boddie) and tobacco budworm, Heliothis virescens (F.), (2)_the boll weevil, Anthonomus grandis grandis (Boheman), (3) the pink bollworm, Pectinophora gossypiella (Saunders) and (4) plant bugs, specifically Lygus spp. Rearing of the predators and parasitoids and identification and the use of behaviour-modifying chemicals are described and discussed.     

大豆地下害虫生物生态控制

针对大豆一般地下害虫为害特点、主要种类生活习性,采取相应的生物生态控制策略进行归纳总结,充分利用自然资源———植物源农药、昆虫病原微生物、天敌进行生物防治,利用生态措施对大豆地下害虫进行控制,为大豆生产实践提供参考。     

现代茶园绿色防控技术在诸暨的实践与应用

本文根据诸暨市茶园主要病虫害及其发生特点,实践应用了现代茶园绿色防控技术,为茶叶安全生产提供保障。     

4种常见草花在三亚地区的栽培管理技术

利用三亚热带气候条件栽培生产草花,尤其是冬春季节生产草花,经济效益好,具有很好的发展前景。从草花育苗、移栽上盆、摘心、肥水管理、病虫害防治等草花栽培的重要技术环节入手,总结4种常见草花在三亚地区的栽培技术,为三亚地区草花的栽培管理提供参考。     

Comparison of two strategies for use of translaminar and contact fungicide in the control of potato late blight in the highland tropics of Ecuador

Strategies based on using the translaminar fungicide cymoxanil for control of potato late blight, caused by Phytophthora infestans, were compared in the highland tropics of Ecuador in three separate field experiments. In one strategy, a commercial formulation of cymoxanil mixed with mancozeb was sprayed sequentially three times early in the season; this was then followed by three sequential sprays of a commercial product containing mancozeb alone. For the other strategy, the same commercial products were alternated. For each strategy, a spray interval of 14 d was used after the contact/translaminar mixture and 10 d after sprays containing mancozeb alone. Both strategies were evaluated with a manually operated knapsack sprayer but with two levels of application quality. High quality was achieved with a constant pressure valve and a new nozzle, while for low quality, fungicide was applied without a valve and using a damaged nozzle. All treatment combinations gave adequate disease control and no consistent effect of application strategy or application quality could be measured on disease severity or yield. However, approximately twice the volume of fungicide was applied using poor quality equipment, regardless of the application strategy. Advantages and disadvantages of the strategies and their potential effects on fungicide resistance are discussed.     

Dormant season foliar sprays of broad-spectrum insecticides: An effective component of integrated management for Diaphorina citri (Hemiptera: Psyllidae) in citrus orchards

Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a global pest of citrus and vector of Candidatus Liberibacter, a bacteria that causes huanglongbing or greening, a devastating disease of citrus. Mature citrus trees are dormant in winter and produce most new shoots in spring, followed by sporadic canopy growth in summer and fall. Young shoots are required for oviposition and nymphal development, but adults can survive and overwinter on hardened leaves. Surviving adults reproduce in spring shoots and their progeny are probably responsible for a large portion of disease spread as they disperse to search for food. Therefore, foliar sprays of broad-spectrum insecticides applied to mature trees in winter were evaluated in a commercial citrus orchard as tactic to reduce pest populations and insecticide use in spring and summer when beneficial insects are most active. A single spray of chlorpyrifos (2.8 kg a.i. ha⁻¹) in January 2007 reduced adult psyllids an average of 10-fold over six months compared to untreated trees. The following year, differences with the untreated control averaged 15-fold for over five months following a single spray of chlorpyrifos, fenpropathrin (0.34 kg a.i. ha⁻¹), or oxamyl (1.12 kg a.i. ha⁻¹) applied in January. Spiders, lacewings and ladybeetles were equally abundant during the growing season in both treated and untreated trees both years (P = 0.05). Thus foliar sprays of broad-spectrum insecticides before spring growth suppressed D. citri for five to six months, with no detectible impact on key natural enemies. This tactic has been widely adopted to control the psyllid in Florida, in some cases area-wide. Additional sprays during the growing season should be based on scouting and targeted at adults before anticipated new flush.     

Investigation into the apparent failure of chemical control for management of western flower thrips, Frankliniella occidentalis (Pergande), on plums in the Western Cape Province of South Africa

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), causes russetting, pansy spot and silvering damage on plums. Despite routine insecticide applications for thrips control, some plum producers report economic losses due to pansy spot damage, pits and holes that render fruit unfit for export. Six commercial plum orchards in two climatic regions in the Western Cape Province, South Africa, were monitored to determine (1) why current management practices based on monitoring and insecticide applications failed to prevent damage in some orchards, and (2) whether WFT is responsible for pitting damage. Western flower thrips was the dominant thrips species in all orchards, though low numbers of Frankliniella schultzei Trybom also occurred. Blue sticky traps were more efficient for monitoring WFT and F. schultzei than yellow traps. Insecticide applications early in bloom and unfavourable weather conditions for thrips flight contributed to very low numbers of WFT on sticky traps during the flowering and fruit set periods. Flower dissections, however, revealed varying levels of oviposition damage to ovaries and fruitlets. Dissections confirmed that WFT enter flowers to lay eggs in the ovaries and other flower parts before petals are fully open. No consistent significant relationship between sticky trap counts and WFT oviposition damage to plums were found, therefore no treatment threshold level could be recommended. Insecticide applications during bloom limited thrips feeding damage, but were too late to prevent oviposition damage. Some oviposition sites developed into typical pansy spots, whilst others formed holes or pits that increased in size as the fruit matured. After insecticide applications ended, and as air temperature increased, WFT populations increased. Weeds and wild vegetation in and around orchards provide a continuous source of potential infestation for as long as the fruit remains attractive and vulnerable to WFT. As oviposition damage by WFT can occur before flowers open, and because of the risk to pollinators when insecticides are applied during flowering, a purely chemical control strategy does not appear to be feasible. A new approach to WFT management is required.     

Comparison of haymaking strategies for cow-calf systems in the Salado Region of Argentina using a simulation model. 1. Effect of herbage mass at cutting and cow stocking rate under a rigid system of management

A simulation model was used to compare the long‐term performance of cow‐calf farm systems under different haymaking strategies on a 100‐ha farm. In the simulation, farm management was based on that which had been developed on Reserva 6, an experimental cow‐calf farm established in 1966 at Instituto Nacional de Tecnología Agropecuaria‐Balcarce Experimental Station, Argentina, where different technologies, including haymaking, have been adapted and applied in order to increase productivity of cow‐calf systems in the Salado Region of Argentina. The management of the system is based on a restricted mating season (2 months), early weaning (5–7 months of age) and forage conservation. The simulations showed that the effect of using hay with respect to the strategy without hay, in terms of calf liveweight (LW) production per hectare, was greatest at the cow numbers that maximized production (290–320 cows) with a proportionate increase of 0.25. On the other hand, the advantage of using hay was smallest when the herbage mass at cutting for hay was 6 t dry matter (DM) ha^?1, particularly when more than 0.50 of the farm area was allocated to haymaking. The differences among the haymaking policies increased with cow numbers, especially at high herbage masses at cutting for hay. The analysis also suggested that the LW production per hectare of cow‐calf farms would be maximized by harvesting 0.40–0.50 of the total farm area and aiming to cut hay at a herbage mass of 4 t DM ha^?1 and with medium quality.