ARTHROPOD PESTS OF OYSTER MUSHROOM (PLEUROTUS OSTREATUS) AND THEIR MANAGEMENT IN WESTERN KENYA

Abstract

Oyster mushroom Pleurotus ostreatus is a major source of food and income in western Kenya. The production of oyster mushroom in this region has been hampered by arthropod pests that cause serious production losses in terms of quality and quantity. Development of an efficient pest control measure is based on the identification of pests infesting oyster mushroom in this region. This study aimed at identifying arthropod pests of oyster mushroom in western Kenya and developing an Integrated Pest Management (IPM) strategy to manage them. Oyster mushroom was established at on-station, old and new mushroom farm sites during short rains in 2012, dry season in 2013 and long rains in 2013. Nylon netting, decis (insecticide), potted Tagetes Minuta + High spawn rate, Nylon net + potted T. minuta + High spawn rate (IPM) as pest control measures were evaluated on their efficacy in managing these pests and enhancing oyster mushroom growth and yield. Pests were sampled per site, season and treatment for identification and data on their numbers per site, season and treatment recorded. Data on days to full spawn run, pinning, first and second flush of oyster mushroom and yield; fresh weight (gms) was also collected. The percent biological efficiency was calculated. Data collected was subjected to Analysis of Variance (ANOVA) using Genstat Version 12 and significant means separated by Tukeys test. Mites Pygmephorus spp. (Acaridae) and dipterans Megaselia scalaris (Phoridae), Bradysia spp. (Sciaridae), Culicoides spp. (Ceratopogonidae) and Anatrichus spp. (Chloropidae) were identified. All pests except Bradysia spp. were reported at the three sites and in all the seasons. The mean number of pests was highest during short rains compared to long rains which recorded the lowest mean number of these pests. Old oyster mushroom farm recorded the highest mean number of these pests with the new oyster mushroom farm recording the lowest mean number. The IPM treatment consisting of Nylon net + potted T. minuta + High spawn rate recorded the lowest mean number of these pests compared to Normal spawn rate. The oyster mushroom in IPM treatment took the shortest duration in terms of days to the various developmental stages of oyster mushroom while recording the highest fresh weight of 150g/kg and percent biological efficiency of 30% after the second flush. There were significant differences (p < 0.05) in terms of mean number of pests and growth and yield of oyster mushroom amongst the different treatments. Thus, this study recommends IPM for management of arthropod pests infesting oyster mushroom in this region. This control measure will not only control the pests but also enhance growth and yield of oyster mushroom for food and income.