The incidence of <em>Bemisia tabaci</em> (Homoptera: Aleyrodidae) and its parasitoids on cassava and associated plants in Uganda

Michael Otim; Samuel Kyamanywa; Stephen Ecaat; James Legg; Dan Gerling

Authors

Michael Otim National Crops Resources Research Institute, Namulonge, P. O. Box Namulonge 7084, Kampala, Uganda. E-mail: motim9405@gmail.com
Samuel Kyamanywa College of Agricultural and Environmental Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda. E-mail: skyamanywa@gmail.com
Stephen Ecaat Farm Radio International/Radios Rurales Internationales. P. O Box 40142, Kampala, Uganda. E-mail: estephen@farmradio.org
James Legg International Institute of Tropical Agriculture – Tanzania, P. O. Box 34441, Dar es Salaam, Tanzania. E-mail: j.legg@cgiar.org https://orcid.org/0000-0003-4140-3757
Dan Gerling Department of Zoology, Tel Aviv University, Ramat Aviv, 69978 Israel

Keywords:

Homoptera, Aleyrodidae, Bemisia tabaci, Hymenoptera, Aphelinidae, Encarsia, Encarsia sophia, Eretmocerus, Eretmocerus mundus, biological control, cassava, parasitoids, population dynamics, pest control, Africa, Afrotropical, East Africa, Uganda

Abstract

Biotic and abiotic factors can influence the population dynamics of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), a key pest of cassava and a vector of several viral diseases, and that of its parasitoids. To gain a better understanding of possible roles these factors, different crops/cropping systems and weeds play in determining B. tabaci population dynamics, cassava fields were surveyed monthly from November 2003 to December 2004 in Buliisa (Buliisa district), Busukuma (Wakiso district) and Lyantonde (Lyantonde district), Uganda. Bemisia tabaci and its parasitoids were more abundant on cassava than on both intercrops and weeds. Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) was the most abundant parasitoid species followed by Encarsia sophia Girault & Dodd (Hymenoptera: Aphelinidae). An undescribed Encarsia sp. was relatively rare. The level of parasitism on cassava was highest at Busukuma (41.7%), followed by Buliisa (37.2%) and Lyantonde (32.2%). The only companion crop that harboured B. tabaci nymphs was sweet potato with 22 nymphs from 20 plants and 68% parasitism. Similarly very low numbers of nymphs were observed on the following weeds: Commelina benghalensis (4 parasitized nymphs from 1340 plants), Melhania sp. (over 76 nymphs from 60 plants with about 60% parasitism), Bidens pilosa (2 parasitized nymphs from 1080 plants) and Euphorbia sp. (8 nymphs from 580 plants with 75% parasitism). This demonstrates that cassava companion crops and weeds in the surveyed locations are not major hosts of B. tabaci. For these two reasons, cassava is the only significant source of cassava-colonizing B. tabaci. Whitefly and disease control on cassava should therefore focus on an integrated management strategy, including breeding for resistance to both constraints, and enhancing natural enemies, in a manner that addresses specific agro-ecosystems.

Cite as: Otim, M., Kyamanywa, S., Ecaat, S., Legg, J. & Gerling, D. 2018. The incidence of Bemisia tabaci (Homoptera: Aleyrodidae) and its parasitoids on cassava and associated plants in Uganda. Israel Journal of Entomology 48 (2): 157–176. <published 27 August 2018>

DOI: 10.5281/zenodo.1403999

urn:lsid:zoobank.org:pub:2C2E529A-241D-4253-9BC7-F90367F66EB0