Influência de sistemas de plantio e armadilha adesiva na incidência de <em>Frankliniella williamsi</em> Hood na cultura do milho

Abstract

RESUMO.Esta pesquisa objetivou avaliar a influência de diferentes sistemas de plantio de milho e o efeito de armadilha adesiva na incidência de Frankliniella williamsi Hood. Os tratamentos consistiram no plantio direto do milho sobre aveia dessecada com glyphosate, aveia tombada, aveia roçada e plantas daninhas, aveia incorporada e plantio convencional. Alguns tratamentos foram associados a armadilha adesiva de coloração azul, colocada horizontalmente no centro da parcela. Verificou-se que tanto a presença de armadilha quanto os diferentes sistemas de plantio influíram significativamente na infestação das plantas de milho pelo tripes, sendo que os tratamentos "aveia dessecada" e "aveia roçada e plantas daninhas" apresentaram menor incidência do inseto, com esse efeito diminuindo com o desenvolvimento das plantas.Palavras chave: Zea mays, tripes, manejo de pragas, controle cultural. ABSTRACT. Influence of planting systems and adhesive trap on the incidence ofFrankliniella williamsi Hood in crop maize. This research aimed to evaluate the influence of different systems of corn planting and the effect of adhesive trap on the incidence of Frankliniella williamsi. The treatments consisted of sowing the corn seed directly on oats dried by glyphosate, tilt oats, cut oats and weeds, incorporated oats, and also conventional planting. Some treatments were associated with adhesive trap of blue coloration, put horizontally in the center of the plot. Results showed that the presence of traps, as well as the different planting systems influenced significantly on the thrips infestation, and the treatments with "dry oats" and "cut oats and weeds" presented smaller incidence of the insect with a decreasing effect along the plants growth.Key words: Zea mays, thrips, pest management, cultural control. IntroduçãoA cultura do milho (Zea mays L.) é atacada por um grande número de insetos, sendo que as pragas de campo chegam a provocar uma queda de até 30% em sua produtividade (Gallo et al., 1988), o que corresponde a uma perda muito alta para ser desprezada.Além do ataque das pragas tradicionais, em algumas regiões dos Estados do Paraná, Santa Catarina e Minas Gerais, tem sido observada a ocorrência de populações elevadas de tripes (Frankliniella williamsi Hood) nas primeiras semanas após a emergência das plantas, principalmente sob condições de baixa umidade (Albuquerque et al., 1998(Albuquerque et al., e 2000Cruz et al., 1999).O tripes, ao se alimentar, causa a morte das células vegetais, o que resulta no sintoma de folha prateada ou esbranquiçada.Em plantas desenvolvidas, a injúria localiza-se na base do limbo foliar, sem efeito aparente sobre o rendimento de grãos. As plântulas atacadas durante períodos de seca e de temperatura elevada têm o seu crescimento paralisado, o que pode resultar em danos severos e morte das mesmas se a população de insetos for elevada (Gassen, 1996).Everly (1960) descreve lavouras de milho com coloração cinza-esverdeada em decorrência do ataque intenso de Anaplothrips obscurus (Muller), Frankliniella fus...

<b>Evaluation of the behavior of thrips in several ground covers by regression models

“…The different soil cover systems had significant influence over the infestation of thrips in the maize plants, being the cover systems with desiccated oat and mowed oat the ones that presented the lowest incidence of thrips over the evaluated period, these results being confirmed by Albuquerque, Crocomo and Scapim in 2006. The recommendation for the farmer who adopts with the no-till system for maize growing is the adoption of the soil cover system with desiccated oat, which constitutes a good measure in controlling thrips and requires less work.…”

“…As a factual example, the data from the longitudinal study must be considered, in which plants were evaluated at 7, 11, 16, 23 and 31 days after seedling emergence in four cover ground systems with oat. This planned experiment was carried out at FEI, UEM, in order to estimate the average number of thrips in the different ground cover systems (GCS) (Albuquerque et al, 2006). Figure 1 shows, for each ground cover system, the behavior of the number of thrips over the five assessments, whereas Table 1 shows the means and standard deviations of the numbers of thrips, in each evaluation period as well.…”

“…The attack is more intensively evident in the first weeks after the emergence of growing seedlings in water deficit conditions, and they embrace a large range of habitats, especially in tropical regions (Carvalho et al, 2007). In addition to the direct damage caused by feeding, the presence of thrips on plants can also often lead to their death (Albuquerque et al, 2006). Damage caused by thrips can result in a significant production loss, also affecting the quality of the product and, thus, its commercialization (Carvalho et al, 2007).…”

“…According to Albuquerque, Crocomo, and Scapim (2006), in some maize farming located in different municipalities of the states of Paraná, Santa Catarina and Minas Gerais, in addition to traditional pests that cause damage, a high emergence of thrips populations have been observed. The attack is more intensively evident in the first weeks after the emergence of growing seedlings in water deficit conditions, and they embrace a large range of habitats, especially in tropical regions (Carvalho et al, 2007).…”