Effectiveness of selected bio-pesticides in pest and disease management in tomatoes

Abstract

Tomato (Lycopersicon esculentum Mill) is among the most widely grown vegetable crops in Sub- Saharan Africa (SSA), cultivated for both the fresh market and sometimes for processing. However, tomato production is constrained by a number of factors including the abiotic and biotic factors as well as the poor agronomic practices. Among the biotic factors, there are the pests and diseases that lead to low yields. As a result, farmers have relied heavily on the synthetic chemical pesticides as the major control tactics for management of these pests and diseases to ensure increased yield. However, the continuous and excessive use of these synthetic chemical pesticides has caused a negative impact on the ecosystem, human health and on the environment. Certain bio-pesticides have proved to be potential safer and effective alternatives to the synthetic chemical pesticides in crop protection. Therefore, this study was conducted to assess the effectiveness of four selected bio-pesticides in management of tomato pests and fungal diseases. The experiment studied four bio-pesticides Trichoderma viride, Beauveria bassiana, Pseudomonas fluorescens, Verticillium chlamydopsorium against Azoxystrobin – chemical fungicide and the untreated control. The treatments were laid in a Randomized Complete Block Design and the study was conducted at Makerere University Agricultural Research Institute Kabanyolo (MUARIK). The major pests studied included; leaf miners, aphids, thrips, whiteflies and bollworms while the major diseases studied were early blight, late blight, downy mildew and powdery mildew. Treatments were applied after the seedlings had established and thereafter applied at a 10 days interval. Data was collected every after two weeks up to harvesting on 10 randomly selected plants per plot. At harvest, fruit weight was recorded by weighing the quantity of mature ripe fruits obtained per plot using a weighing balance considering four harvesting times. Results from this study showed that all treatments significantly effected on the severity and occurence of late blight, early blight and powdery mildew. Verticillium chlamydopsorium was effective for control of late blight and early blight, Pseudomonas fluorescens was effective against powdery and downy mildew as well as on whiteflies and Beauveria bassiana was effective for control of early blight. Beauveria bassiana improved all the measured plant growth parameters and yield. Therefore, these bio-pesticides should be included among the key control tactics for management of tomato pests and diseases and for increasing yield. Thus, this information is relevant to tomato growers who aim at increasing tomato productivity while protecting the environment or those who practice organic farming