Components of resistance to banana weevil (Cosmopolites sordidus) in Musa germplasm in Uganda

Abstract

A field screening trial undertaken in Uganda showed that a number of Musa L. (Musaceae) cultivars and hybrids displayed high levels of resistance to banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), while most highland banana cultivars tended to be susceptible to weevil attack. In this study, research was undertaken to determine modalities of resistance to banana weevil. Laboratory studies suggested that all cultivars were attractive to the weevil and that females freely oviposited on all cultivars. While some differences were found between cultivars in attractivity and egg numbers, these were not related to subsequent damage. Therefore, antixenosis does not appear to play an important role in host-plant resistance to banana weevil. Larval survivorship rates in living corms were, for the most part, low on resistant cultivars, suggesting that antibiosis mechanisms offer the primary avenues of resistance. In the laboratory, development was slower on some resistant cultivars although survivorship rates on excised corm material were not as well related to levels of resistance as that on living material. Sap appeared to play a minor role in reducing egg eclosion rates on some resistant cultivars. Methanol extracts from Kayinja, a resistant cultivar, inhibited larval development on corms of susceptible cultivars in the laboratory.

Assessing the Effectiveness of Ethnomedicinal Products on Banana Weevils Using REML

“…Improved varieties had a high host resistance as compared to the landrace varieties. This is in agreement with Reddy et al, [30]; Kiggundu [31] who reported that improved varieties expressed higher host resistance to banana weevils than the "Matooke" (AAA) type. The results of study were also in agreement with findings by Speijer et al, [32 but contradicted another study by Bagamba, Burger and Tushemereirwe [33] in which, "Gonja" was found to have higher survival rate than "Ndizi".…”

Infestation of the banana root borer among different banana plant genotypes

“…Although rhizome hardness can affect the insects (ORTIZ et al, 1995), it is likely that the presence of secondary compounds is the main factor that influences the banana root borer. Previous research has shown that resistance to antibiosis strongly affects the banana root borer, since it can influence larval development (ABERA, 2000;NIGHT et al, 2010) and reduced egg viability when the eggs are laid in resistant plants (KIGGUNDU et al, 2007). It has been reported that genotypes susceptible to banana root borer may contain specific volatiles (NDIEGE et al, 1991(NDIEGE et al, , 1996, but females have no ability to discriminate between susceptible and resistant genotypes (KIGGUNDU et al, 2007), which may explain the similar distribution of adults reported in the banana orchard in this study.…”

“…To expand the options for adequate pest management, researchers showed that planting bananas with genotypes that confer different levels of pest resistance to the plant is a possible strategy for management of the banana weevil. However, these studies have thus far been Oliveira et al restricted to Africa (ORTIZ et al, 1995;KIGGUNDU et al, 2003a, b;KIGGUNDU et al, 2007;NIGHT et al, 2010;SADIK et al, 2010).…”

Influence of plant and residue age on attraction, acceptance and larval survival of the banana weevil Cosmopolites sordidus (Coleoptera: Curculionidae)

“…Larval survivorship rates were also similar in plants and residues. However, we caution that survivorship rates determined on material excised from growing plants in laboratory studies may be elevated as observed by Kiggundu et al (2007) on resistant cultivars such as 'Yangambi Km5'.…”

“…Antibiosis appears to be the major avenue of resistance Kiggundu et al, 2007). Nevertheless, antibiotic mechanisms appear to break down after harvest.…”