Control of Post Harvest Bacterial Diseases of Tomato in Abia State, South Eastern Nigeria.

Abstract

A laboratory experiment was conducted at Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria to assess the effect of pre-heat treatments and some plant extracts in the control of bacterial soft rot (Erwinia carotovora) and fruit spot (Xanthomonas vesicatoria), the two major post harvest bacterial diseases of tomato fruit (Lycopersicon  esculentum) in Nigeria. The design of the experiment was a randomized completely randomized block design (CRD) with 4 replicates. A batch of tomato fruits was subjected to hot water bath at different temperatures and time duration: 50, 60 and 70⁰C at different time duration; 10, 20 and 30mins with cold water as the control. While another batch was treated with cold and hot water plant extracts consisting of; Azadirachta indica seed, Garcinia kola, Zingiber officinale, Piper guineense seed and Myristica fragrans seed at different concentrations (10, 20, 30%). Data obtained showed that subjecting tomato fruit to a temperature of 50⁰C for 10mins recorded the longest shelf life (storage period) and was significantly different (P=0.05) from the control experiment. Increase in temperature regime above 50⁰C to 70^oC resulted to decrease in shelf life/storage period.  At higher temperatures and longer time duration of 60⁰C to 70⁰C for 30mins, the fruits became physiologically unstable accompanied with skin crumpling and cracks with leakage leading to rapid rot and decay of the fruits. Results also showed that all the five plant extracts were effective in inhibiting the growth of bacterial spot pathogen and the soft rot diseases of tomato in vitro (P<0.05) when compared with the untreated control. However, cold water extracts of A. indica, Z. officinale, P. guineense significantly inhibited bacterium growth by 76.26-78.92 % more than the hot water extracts.

Keywords: Pre storage treatment, plant extracts, fruit rot.