Incidence and severity of the mistletoe Tapinanthus globiferus on guava and lime and its mechanical control in the Gezira State, Sudan

Abstract

Mistletoes of the genus Tapinanthus (Loranthaceae) are stem hemiparasite comprising about 250 species in East and West Africa. Mistletoe (Tapinanthus globiferus) (A. Rich.) van Tieghan, which possess straight pentamerous colourful red flowers, causes severe damage to lime (Citrus aurantifolia Swingle) and guava (Psidium guajava M.) in orchards along the Blue Nile banks in central Sudan. The main purpose of this research was to find an environmentally friendly approach for the management of mistletoe in orchards fruit trees. Specific objectives were: to evaluate the presence, degree of damage caused by the parasite, and the awareness of farmers, and then use this information to assess possible control measures. A survey was conducted in 2009/2010 by interviewing 186 farmers in the study area (Wad Medani and Hisahisa Provinces) in the Gezira State, a major producer of fruits in the State. The survey results indicated that the incidence of the parasite was 73% in Wad Medani and 23% in Hisahisa. About 70% of the respondents were familiar with the parasite, and 64% of the interviewed farmers practiced traditional pruning by using logging axe, most of the farmers failed to control the parasite. Severely infected orchards were selected for assessment of potential preventive control methods using severe pruning, regular pruning using long handled shears and traditional pruning with logging axe. The results revealed that severe pruning reduced infection by 76% and severity index by 94% in guava. However, traditional pruning using axe reduced infection by only 2.2% and severity by 45%. Regular pruning in lime trees using long handled shears reduced infection by 50% and severity index by 80%. Using the traditional methods in lime orchards reduced severity by 18% with no effect on infection percentage. In conclusion, severe pruning and regular pruning using long handled shears were found to be effective in controlling the parasite in guava and lime trees. These methods were easy to accomplish, and not expensive.