Path coefficient analysis to assess yield losses due to a multiple pest complex in cotton in Thailand

Abstract

A network of experiments was established in three different agroecological areas at the periphery of the Central Plain of Thailand during three successive years to assess the effect of a multiple insect pest complex on cotton yield loss. A large range of combinations of jassid and bollworm injuries was achieved from the application of several insecticide treatments and sowing dates. Other pests were of minor incidence. Seed-cotton yield varied from 0 to 3600 kg/ha, and yield losses due to pests ranged between 0 and 100% of the attainable yield. Damage mechanisms were addressed through path coefficient analysis of the interaction between injuries and plant compensation. Before boll production, jassids were the most serious pests, while bollworms had a positive effect on vegetative growth. At the fructification stage, bollworms were very harmful, while sucking insects such as jassids became progressively less important. Injuries did not necessarily lead to yield losses because of the plant compensation ability. Cotton response to pest injuries depended on the development stage and crop status. Decisions made on cotton protection against pests should thus consider the development stage of the crop and interactions between injuries instead of the traditional single pest population threshold. This study of a plant-pest system exemplifies the need to incorporate plant compensation processes in the design of pest management programmes aiming at reducing insecticide use.phytosanitaire doit donc considérer le stade de développement de la culture et les interactions entre les dégâts des multiples ravageurs plutô t que le traditionnel seuil d'intervention individuel pour chaque population d'insecte. Cette étude du système plante -ravageurs montre l'importance d'incorporer les processus de compensation de la plante dans la mise au point des programmes phytosanitaires destinés à réduire l'utilisation d'insecticide.

Primary and Secondary Yield Losses Caused by Pests and Diseases: Assessment and Modeling in Coffee

“…In perennial crops, studies on apple and other stone fruits reported yield losses that reached up to 5% in the Netherlands [27]. In Thailand yield losses of cotton were estimated up to 100% [28]. In coffee, yield losses were reported from 13% to 45% in Brazil [29].…”

Crop damage increases with pest species diversity: evidence from potato tuber moths in the tropical Andes

“…Surprisingly, the study of the effects of multiple pests on agricultural productivity has remained largely disconnected from the ongoing debate on how species diversity affects the functioning of ecosystems. Whereas the former line of research has focused mostly on the effect of non‐additive species interactions in crop consumption (Castella, Dollona & Savary 2005; Davidson, Peairs & Khosla 2007), the latter has concentrated on additive mechanisms, independently of overall abundance, by which species diversity influences resource consumption, with emphasis on terrestrial plant communities (Loreau & Hector 2001; Hooper et al. 2005; Callaway 2007).…”

“…tivity has remained largely disconnected from the ongoing debate on how species diversity affects the functioning of ecosystems. Whereas the former line of research has focused mostly on the effect of non-additive species interactions in crop consumption (Castella, Dollona & Savary 2005;Davidson, Peairs & Khosla 2007), the latter has concentrated on additive mechanisms, independently of overall abundance, by which species diversity influences resource consumption, with emphasis on terrestrial plant communities (Loreau & Hector 2001;Hooper et al 2005;Callaway 2007). Both additive and nonadditive insect species interactions probably have an impact on plant damage (Kaplan & Denno 2007), but, so far, insights from studies of the diversity-function debate have rarely been applied to understanding the functional significance of herbivore insect diversity in agricultural systems (Hammons et al 2009).…”

Shannon information theory a useful tool for detecting significant abiotic factors influencing the population dynamics of Helicoverpa armigera (Hübner) on cotton crop

“…The H. armigera incidence mainly based on the crop stage and this report is confirmed with earlier reports (Leonardo and Miriam, 2002) where the authors mentioned that H. armigera larvae were confined to succulent plant parts like growing tips, small squares, big squares and bolls. Bollworms had a positive effect on vegetative growth and were very harmful at fructification stage on cotton crop (Castella et al, 2005). This is due to the continuous availability of food in nature which plays an important role in seasonal carryover by shifting of the pest from one host to another (Singh and Singh, 1975).…”