Distribution and damage status of moringa moth (Noorda blitealis Walker) on Moringa stenopetala Baker (Cufod.) in southern Rift Valley of Ethiopia.

Abstract

Moringa stenopetala Baker (Cufod.) commonly called as African Moringa, is a native or endemic multipurpose tree species in East Africa. An insect pest, moringa moth (Noorda blitealis Walker) has become an important pest on moringa trees in Southern Rift Valley of Ethiopia. The present study was carried out to determine the distribution and damage status of moringa moth (N. bliteails) on M. stenopetala in the study areas of Konso, Derashe and Arbaminch Zuria districts of Southern Rift valley of Ethiopia. Qualitative and quantitative data of defoliation severity were collected during the periods of heavy defoliation in major and minor rainy seasons of the year 2011. The damage rating values were taken by using the Arc GIS 9.3 and Arc GIS 10.0 softwares and the SNNPR data map of Ethiopia was used to make the distribution map. The visual damage rating mean values of the trees and the defoliation percentage were determined with respect to seasonal variations, cropping systems, altitudinal differences, and host plant age differences. The extent of defoliation by moringa moth was recorded maximum during the major rainy season than minor rainy season and the reduced leaf biomass production of moringa trees (31-70%) were recorded during the month of July at the mixedcropping system condition and more than75% recorded during the months of July and December for mono-cropping system condition. Moderate to severe defoliation was recorded within the altitude range of 12001600 m. a. s. l. The leaves of old trees having large trunk and canopy size were more resistant to moringa moth attack than the leaves of younger trees that have relatively small trunk and canopy size during both the major and the minor rainy seasons. Succulent and younger leaves were grown after continuous and periodic leaf harvest, which were more susceptible for attack by moringa moth larvae than tender and older leaves which stayed for longer periods on the tree without continuous harvest. This study was helpful in identifying the gaps concerning the basic information on spacial and seasonal distribution of moringa moth in these areas of Ethiopia. Further study could be conducted on various methods of managing this pest on moringa trees and growers may have enough quantity and better quality of moringa vegetables that could be produced.