Manejo químico de dalbulus maidis (hemiptera: cicadellidae) para redução dos efeitos dos enfezamentos no milho por molicutes

Abstract

Corn is one of the most produced and consumed cereals in the world. Due to its chemical composition of high nutritional value, essential for animal and human nutrition. Like other crops, this plant is attacked by pests, and the corn leafhopper (Dalbulus maidis) is the most harmful, as it is a vector of pale and red stunt and stripe virus. Due to the high susceptibility of corn cultivars to stunting, a period of water deficit and high numbers of insecticide sprays, producers face many challenges managing the pest, which result in large crop losses. The objective of this work was to evaluate management strategies for insecticide applications and the delay in decision making. The experiments were conducted in a randomized block design, with 5 management methods and 4 replications. Each repetition was composed of 12 lines, 8 meters long and between lines of 0.5 meters. The treatments (experiment I) were: T1 (control): As an attractant for leafhoppers, “bait corn” was planted 30 days before the experiment was sown and mowed in V3. The parameters evaluated were severity of stunt symptoms and grain productivity. The results were subjected to analysis of variance, taking into account the location, stunting scores and grain productivity. The variables evaluated were subjected to normality and homogeneity of variance tests. When the F value was significant, the productivity means were compared by the Tukey test at 5% significance, using the Genes Software. Shortness scores were analyzed using Friedman’s non-parametric test, in the BioEstat 5.0 software. The severity of corn stunting is lower when four applications of insecticides are made for the corn leafhopper, which is linked to better productivity. Grain productivity was higher where insecticides were used. The delay in insecticide applications was not efficient for both the severity of stunting and grain productivity. This result may be related to the different conditions of each cultivation site.Therefore, although chemical control is an alternative that reduces the incidence of stunting, more research is needed to evaluate the effectiveness and timing of insecticide application via foliar use.