Populational fluctuation of lace bug in cassava

Danilo Renato Santiago Santana,Harley Nonato De Oliveira,Thiago Alexandre Mota,Elisângela De Souza Loureiro,Patrícia Paula Bellon,Auro Akio Otsubo

doi:10.1590/1808-1657000602015

Abstract

ABSTRACT: Vatiga illudens is a pest of economic importance for the cultivation of cassava. Knowing the time of incidence of this insect in combination with environmental factors enables control strategies. The objective of this study was to determine the population dynamics of V. illudens in cassava cultivars and the correlation of these insects for climatic factors in Dourados, Mato Grosso do Sul. Four cultivars of cassava were evaluated: Kiriris, N-25, IAC 90 and Fécula Branca. Population assessment of the lace bug was conducted over 18 months observing 2 crop cycles. Fortnightly, they were randomly sampled four central plants of each plot and five leaves from the middle third of each plant, quantifying the number of nymphs and adults per leaf. Twenty months after planting cassava, two central rows of each plot were harvested and measured productivity in kg ha-1. The experimental design was randomized blocks with four treatments and two replications. The peak population of nymphs and adults for the first crop cycle occurred during the months from March to May. For the second cycle, these population indices happened in the months from January to April. Cultivar Kiriris showed the highest mean number of nymphs and adults per leaf cassava and cultivar IAC 90, the lowest number of insects. There was a negative correlation between the population of adult insects and root yield. The maximum, mean and minimum temperatures affected the population of nymphs V. illudens. These results are fundamental to define management strategies for control of lace bug.

Highlights

IntroductionThe center of origin of cassava (Manihot esculenta Crantz) (OLSEN, 2004), is the second largest producer of it in the world (IBGE, 2014)
MATERIAL AND METHODSBrazil, the center of origin of cassava (Manihot esculenta Crantz) (OLSEN, 2004), is the second largest producer of it in the world (IBGE, 2014)
The population of nymphs had their population peak in the month of March and April and a new increase of the population in May (Fig. 2). This population began to increase in November, reaching its population peaks in the months of December to February and again in April (Fig. 2)

Summary

Introduction

The center of origin of cassava (Manihot esculenta Crantz) (OLSEN, 2004), is the second largest producer of it in the world (IBGE, 2014). It has a high socioeconomic importance, as cassava is the main source of carbohydrates and subsistence for the most deprived populations, besides being an important basis for animal feed and starch production (SOUZA; FARIA, 2006). Despite its low national participation, the sector has shown great growth potential due to the region’s edaphoclimatic conditions, the implantation of starch processing industries and the high consumption of table cassava, constituting, an important economic alternative for the producers (OTSUBO; PEZARICO, 2002). It is estimated that about 200 arthropod species causes damage to cassava in the Americas, but there are gaps in the knowledge of production losses, population levels of control and economic damage (BELLOTTI et al, 1999)

Objectives

Results

Conclusion