Resistance of cassava genotypes to Vatiga manihotae (Drake 1922) (Hemiptera: Tingidae)

Abstract

Vatiga manihotae (Drake 1922) (Hemiptera: Tingidae) is an important cassava pest due to the great potential damage and the increasing population in recent years. However, few studies about bioecology and control of the cassava lace bug have been conducted and their results don't provide adequate control strategies. An alternative to maintain the population below economic injury levels is through the adoption of host plant resistance. To improve the understanding about the bioecology and find new sources of resistance in cassava, the biological parameters and demographics of V. manihotae on five cassava genotypes (Santa Helena, MEcu 72, Col 22, Clone 02 and Clone 03) under controlled conditions (25±2°C, 14L/10D) were evaluated. Duration and viability of the stages, the period egg-adult, sex ratio, the pre-oviposition period, fecundity and longevity of male and female was determined, and a fertility life table was prepared. Insects fed on MEcu 72 showed increased nymphal, egg-adult, and pre-oviposition periods and reduced female fecundity and longevity in comparison to the other genotypes. Demographic parameters (Ro, r m , T, DT) showed a significant impact on the growth potential of V. manihotae fed on MEcu 72 indicating that the populations would diminish over time. The combined effect of these parameters indicated that MEcu 72 has resistance on V. manihotae specimens hindering their development.

Short Communication: First record of the cassava lace bug Vatiga illudens (Drake, 1922) (Hemiptera: Heteroptera: Tingidae) from East Java, Indonesia

“…Since a decade ago, V. illudens has been recognized as a devastating pest of cassava in the Neotropical Region, mainly in Brazil (Bellon et al 2017;da Silva Wengrat 2020). However, V. illudens infestation has been progressively increasing outside its native range.…”

Peroxidase and polyphenol oxidase activity in cassava genotypes infested with Phenacoccus manihoti

“…Eleven of the 18 cassava genotypes evaluated were improved to increase yield: B36/2007, B125/2007, 525/ 2007, 553/2007, 586/2007, 859/2007, 913/2007, 1030/2007, and IAC Caapora. The remaining seven were landrace genotypes: Cascuda, Caiuá (Olho Junto), Santa Helena (Fécula Branca), Baianinha, Corrente, MEcu 72, and Peru 334the former five landraces are widely grown in the center-south region of Brazil, whereas the latter two have been demonstrated to have some level of resistance to insects (CIAT, 1999;Barilli et al, 2019;Wengrat et al, 2020).…”

“…The cultivation of resistant genotypes may be a promising alternative to maintain P. manihoti population below economic injury levels and could be compatible with biocontrol strategies (Bellotti & Arias, 2001). Among the cassava genotypes, MEcu 72 could be a good candidate for resistance to P. manihoti, because it is resistant to various sap-sucking insects, such as whitefly and lacebug, decreasing their reproductive rate and increasing whitefly nymphal mortality (Carabalı ´et al, 2010;Barilli et al, 2019;Wengrat et al, 2020). Phenolic compounds and particularly rutin were involved in cassava resistance against P. manihoti by lowering their weight and slowing their development (Calatayud et al, 1994;Calatayud, 2000).…”