Vegetative growth and yield of tomato (Lycopersicum esculentum Mill.) in response to the systemic insecticide phorate

Abstract

An. Soc. Entomol. Brasil 27(3): 443-449 (1998) Crescimento Vegetativo e Produção de Tomateiro (Lycopersicum esculentum Mill.) em Resposta ao Inseticida Sistêmico Forate RESUMO -O efeito do inseticida sistêmico forate no crescimento vegetativo e produção de tomateiros (Lycopersicum esculentum Mill.) foi estudado em casa de vegetação. Três dosagens de forate foram estudadas: 1,5, 7,5 e 13,5 mg i.a./ 1.5 L vaso e um controle (sem aplicação do inseticida). As plantas foram colhidas 17, 32, 51, 69 e 90 dias após o plantio. Análises de regressão não mostraram efeito significativo de doses do inseticida na altura da planta e no comprimento de raiz. Entretanto, efeito negativo genérico de forate foi observado na área foliar, no peso seco de raiz e parte aérea, e no peso fresco de frutos. Baseado em modelos de regressão múltipla, área foliar máxima foi conseguida com 6,7 mg i.a./vaso e máximo peso seco de parte aérea e raíz foram obtidos sem aplicação de inseticida e com 0,1 mg i.a./vaso, respectivamente. Dosagens de forate próximas ao limite inferior das dosagens recomendadas para tomateiro (1 kg i.a./ha) favoreceram o aumento da área foliar das plantas de tomate, mas este aumento não se traduziu em aumento de produção. Forate foi ligeiramente detrimental ao crescimento de parte aérea e raíz , o que levou a uma menor produção em plantas tratadas com este inseticida.PALAVRAS-CHAVE: Tomateiro, inseticida sistêmico, crescimento vegetativo.ABSTRACT -The effect of the systemic insecticide phorate on vegetative growth and yield of tomato (Lycopersicum esculentum Mill.) was studied in the greenhouse. Three dosages of phorate (1.5, 7.5, and 13.5 mg a.i./ 1.5 L pot) were applied along with a control (without insecticide application). The plants were harvested at 17, 32, 51, 69, and 90 days after tilling. Regression analysis did not show any significant effect of insecticide dosages in plant and root length. However, an overall negative effect of phorate was observed on leaf area, shoot and root dry weights, and fruit fresh weight. Based on multiple regression models, maximum leaf area was obtained with 6.7 mg a.i./pot and maximum shoot and root dry weights were obtained with no insecticide application and 0.1 mg a.i./ pot, respectively. Higher fruit fresh weights were also obtained without phorate application. Dosages of phorate close to the lower range recommended for pest

Formulations of Melia azedarach to Control Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) Larvae in Corn and Plant Enhancement

“…According to Ford et al (2010), the neonicotinoids imidacloprid and clothianidin can trigger plant defense mechanisms similarly to salicylic acid transcriptional mechanisms, which may also increase plant growth. Moreover, effects of insecticide treatment on plant growth depend on the plant species, soil characteristics, insecticide, and the active ingredient concentration (Guedes et al 1998).…”

“…Furthermore, applied systemic pesticides have shown direct and indirect effects on plant development (Aramaki et al 2013). For example, carbofuran metabolites improved growth of pea plants (Lee 1976) and low rates of phorate applied in soil increased the leaf area of tomato plants (Guedes et al 1998). Growth improvement in chickpea plants was obtained using low insecticide concentrations, especially carbofuran (Tiyagi et al 2004).…”

Direct effects of insecticides on common ragweed-implications for natural enemy exclusion trials

“…5) For example, the application of phorate reduced root and shoot growth and yield of tomato and pearl millet. 6,7) Some organophosphate insecticides such as dimethoate and chlorpyriphos also caused phytotoxicity to several (non-target) weed species (i.e., annual forbs, Poa spp. ), in particular by inhibiting or slowing weed seed germination.…”