Efeito do armazenamento na compatibilidade de fungicidas e inseticidas, associados ou não a um polímero no tratamento de sementes de feijão

Abstract

RESUMOEstudou-se neste trabalho a compatibilidade de produtos químicos, associados a um polímero no tratamento de sementes de feijão, estabelecendo-se ainda, o período máximo de armazenamento. Sementes de feijão da cultivar Pérola foram submetidas aos seguintes tratamentos: 1) testemunha; 2) carbendazin + thiram + fipronil + polímero; 3) carbendazin + thiram + fipronil; 4) carbendazin + thiram + thiodicarb + polímero e 5) carbendazin + thiram + thiodicarb. Avaliaram-se emergência, eficiência no controle de lagarta elasmo (Elasmopalpus lignosellus) e sanidade das sementes. Nos resultados dos parâmetros emergência e controle de elasmo, os tratamentos associados ao inseticida fipronil foram superiores aos demais; na sanidade das sementes, os tratamentos com o inseticida thiodicarb foram mais eficientes, indicando ser esse o inseticida mais compatível à mistura com os fungicidas carbendazin + thiram aos 150 dias de armazenamento. Os produtos testados podem ser utilizados no tratamento de sementes de feijão, e as sementes tratadas armazenadas por até 120 dias antes da semeadura.Palavras chaves: armazenamento de sementes, Elasmopalpus lignosellus, sanidade de sementes, testes fisiológicos. ABSTRACT EFFECT OF THE STORAGE IN THE COMPATIBILITY OF FUNGICIDES AND INSECTICIDES ASSOCIATED OR NOT TO A POLYMER IN DRY BEAN SEED COATINGThe compatibility of chemical products in dry bean seed coating associated to a polymer was studied in this work. Also, the maximum period of storage for these seeds coated with polymer and defensives was established. Dry beans, from cv. Pérola were submitted to the following treatments: 1) control; 2) carbendazin + thiram + fipronil + polymer; 3) carbendazin + thiram + fipronil; 4) carbendazin + thiram + thiodicarb + polymer and 5) carbendazin + thiram + thiodicarb. The evaluated parameters included emergency, lesser cornstalk borer (Elasmopalpus lignosellus) efficiency control and seed pathology. For the parameters emergency and borer control the best results were obtained with the treatments including fipronil insecticide. As for seed pathology, treatments with thiodicarb insecticide were more efficient, indicating a suitable compatibility of this insecticide with the fungicides carbendazin + thiram until 150 days of storage. The products tested could be used in dry bean seed dressing, and the treated seeds could be stored up to hundred and twenty days prior to planting.

Insecticide Treatment and Physiological Quality of Seeds

“…(Oliveira & Cruz, 1986;Kashypa et al, 1994;Nascimento et al, 1996). In corn crops, significant depletion in seed vigor were observed by Bittencourt et al (2000) after cabofuran application, similarly acknowledged by Fessel et al (2003) who reported reduction in longevity, vigor and seedling emergence speed of corn crops after treating seeds with deltametrine and pirimiphos-methyl in high doses. Silveira et al (2001) observed a smaller seedling radicular development after applying the insecticide phipronil on seeds.…”

“…On the other hand, Barbosa et al (2002), when treating bean seeds with the insecticides imidacloprid and thiamethoxam, verified that the active ingredients provided some improvement in the crop's agronomical traits, as a result, increasing productivity. Barros et al (2005) verified greater percentage on bean seeds germination in treatments using the insecticide phipronil. However, Tavares et al (2007) observed no difference on germination and vigor when using different doses of thiamethoxam in soybean seed treatment.…”

“…Nevertheless, Castro et al (2008) observed higher vigor in soybean seeds treated with imidacloprid. Bittencourt et al (2000) have found no effects of the insecticides thiodicarb, imidacloprid plus thiodicarb in corn seedlings emergence. However, treated seeds were not stored in these studies.…”

“…Seed physiological quality is influenced by genetic traits inherited from their parent trees, as well as germination and vigor, which are affected by environmental conditions, harvesting methods, drying process, processing, storage and packing (Zambolim, 2005). Nevertheless, storage of insecticide treated seeds may cause significant reduction on both germination and vigor as demonstrated by a number of authors (Bittencourt et al, 2000); (Gotardo et al, 2001). This fact might be related to deterioration caused by the use of insecticides, which induce the formation of free radicals and subsequent oxidative stress (Braguini, 2005).…”

“…Nevertheless, evidences obtained from some studies have shown that some seed dressing products, under certain situations, may cause reduction in germination as well as seedling survival due to the phytotoxic effect. Significant vigor decreases were induced by carbofuran in corn seeds after treatment and a subsequent 30-day-period storage (Bittencourt et al, 2000). Corn seeds treated with the insecticides, such as deltametrine and pirimiphos-methyl in high doses (Fessel et al, 2003) lowered longevity, vigor and emergency speed of seedlings.…”