Status and effects of insect pests on the cashew (Anacardium occidentale L.) in southern and central zones, Tanzania

Abstract

This study was conducted from February to March and July to August 2019 in twenty-four (24) cashew fields located in the southern and central zones of Tanzania. In each zone, three districts were selected based on cashew production reports, and in each district, four farms were selected. In each farm, ten fully-grown cashew nut trees were randomly selected and assessed for infestation by sucking insect pests. The insect pests were assessed within quadrants of one-meter length placed at the north and south of the canopy of the cashew tree. The total number of insect pests, susceptible shoots and nuts, both clean and damaged were recorded. Insect samples were collected and identified at the Tropical Pesticides Research Institute, Arusha Tanzania. Twenty-seven (27) key informant farmers were interviewed using questionnaires and farmers group discussions in both zones. The study revealed a number of both known and first recorded insect pest’s attacks that cashew nut. The commonly known insect pests identified include Helopeltis sp, Pseudotheraptus wayi, Selenothrips rubrocinctus and Mecocorynus loripes, and newly recorded were Miphetophora sp., Plaesiorrhira sp., Diplognatha gagates, Systates sp, and Aphis sp. The incidence and diversity of these cashew sucking insect pests differed in terms of abundance and distribution within cashew fields. Most abundant insect pests were Helopeltis sp. with incidences of 46.7%. Further research is required in studying biology, ecology population dynamics and abundance of first reported and identified insect pests to determine specific periods for intervention and develop methods (species-specific) for effective pest management in Tanzania.