Características físico-químicas de grãos de milho atacados por Sitophilus zeamais durante o armazenamento

Abstract

RESUMOO objetivo do trabalho foi avaliar os danos físicos e químicos causados por insetos adultos da espécie Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), criação própria sob condições controladas (25±5 °C e 60±10% UR), em grãos de milho híbrido (Zea mays L.) AS-32, oriundos de lavoura experimental, durante três períodos de armazenamento: 30, 60 e 120 dias. O experimento ocorreu nas mesmas condições e foi constituído de quatro repetições de 600 g de grãos com 150 insetos para cada tratamento. As análises realizadas também com o produto "in natura" foram: umidade, perda de peso dos grãos, peso de 1000 grãos, tecnológica de defeitos, extrato etéreo, proteína bruta e variação populacional (emergência, mortalidade e sobrevivência dos insetos). No maior período avaliado (120 dias) ocorreram as maiores perdas de peso, presença de grãos carunchados, grau de umidade, variação populacional e menor peso de 1000 grãos e extrato etéreo. Pode-se concluir, com base nesses resultados, que quanto maior o período de contato dos insetos com os grãos maiores são os danos causados e os prejuízos para os produtores.Palavras-chave: perda de peso, extrato etéreo, proteína, gorgulho-do-milho Physicochemical characteristics of corn damaged by Sitophilus zeamais during storage ABSTRACT The objective of present study was to evaluate the physical and chemical damage caused by the adult insects of the species Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), self creation under controlled conditions (25 ± 5 °C and 60 ± 10% RH) in grains of hybrid maize (Zea mays L.) AS-32, collected from an experimental farm for three storage periods: 30, 60 and 120 days. The experiment was conducted under the same conditions and consisted of four repetitions of 600 g of grain with 150 insects for each treatment. The analysis also performed with the product "in natura" were: moisture, weight loss of grain, 1000 grain weight, technological defects, ether extract, crude protein and population variation (emergence, mortality and survival of insects). The longest study period (120 days) showed the largest weight loss, presence of insect attacked grains, moisture content, population variation, and lower 1000 grain weight and lipids. One can conclude, based on these results, that the greater the contact period of insects with grains, the greater the damage and losses to farmers.

Chemical pesticides and vegetal extracts on Sitophilus zeamais control in stored corn grains

“…K. C. et al high rate of population growth from the second evaluation period, as well as high water content in grains. This information is confirmed by Silva et al (2003) and Antunes et al (2011), who observed that an increase in humidity of wheat and corn grains as S. zeamais population increased, further reinforcing the hypothesis that insects have influence on the increase in grain moisture content. In the first period, the moisture values that were high may have suffered interference from the environment and the initial period of storage, tending to the hygroscopic equilibrium of plots with settings.…”

Quality of stored grain of corn in different conditions

“…According to the analysis results, the corn had deteriorated with lower levels of crude protein and ether extract than corn quality, with a slight increase in rates in the three months of storage and reduction at twelve months. According to ANTUNES et al (2011) insects first attack the endosperm of maize grains, though the insects consume more germ, causing a greater decrease in fat and protein may even increase for two reasons: first, for normal aspect ratio due to increased consumption of fat and less protein and, secondly, because the sample can be determined along with the grain protein, the protein of insects and, thus, can also increase the percentage. *Significant at 5%, the t test.…”

Utilization of Different Corn Fractions by Broilers

“…For instance, Krabbe et al (1994) found that the level of fungal infection in corn is proportional to feed ME reduction, especially due to reduced EE content. Antunes et al (2011) observed that insect infestation level influences the chemical composition of the corn grain. Therefore, we hypothesize that the corn used in the present experiment presented better quality than those evaluated in the previously mentioned, including a smaller fraction of insect-damaged grains.…”