Antixenosis Resistance in Sugar Beet Varieties to Long Snout Weevil Lixus incanescens Boh. (Col.: Curculionidae)

Abstract

In plants, antixenosis resistance could reduce injury and yield loss; they can produce selection pressures on insect herbivores that lead to pest resistance. Traditionally, sugar beet long snout weevil, Lixus incanescens Boh. (Col.: Curculionidae), is one of the serious pests causing sugar beet losses. In the present study, antixenosis resistance was evaluated in 11 varieties of sugar beet including Pars, Torbat, Ekbatan, SBSI019, Rizofort, Puma, Dorothea, Brigita, Pecora, Nagano and Jolgehin a field trial from 2013 and 2014 years in Qazvin province, Iran. A randomized complete block design with their replications was used. The results showed that in both years, in the first 24 h experiment after release the lowest and highest densities of pest (No. adult/plant) were seen on Pars (2.99) and Dorothea (2.83) varieties, respectively, as opposed the lowest antixenosis resistance were found on Brigita (8.66) and Nagano (8.83) cultivar, whereas on other cultivars showed intermediate values. In Pars, Brigita and Nagano varieties the number of adult weevils (adult/plant) increased rapidly during the first 24 h, but after which there was a decline to the minimum on about the fifth day. The results of data analysis to investigate the mechanism of free choice antixenosis in the years 2013 and 2014 showed that there are no significant differences between experimental blocks and among cultivars tested. As a result, our findings showed that above mention variety can be used in integrated management plans of sugar beet long snout weevil, and with regionally adapted varieties and excellent seed quality we strive for excellent varietal performance in all growing regions of the Iran. Keyword: Antixenosis, Lixus incanescens, Resistance, Sugar beet, Weevil.