Microplot evaluation of Brassica crop residues for control of Fusarium wilt of watermelon, 2008

摘要

A microplot experiment was conducted to evaluate the potential of using the residues of Brassica or other crops to control Fusarium wilt of watermelon caused by Fusarium oxysporum f. sp. niveum (FON). The experiment was conducted atthe University of Maryland’s Lower Eastern Shore Research and Education Center, Salisbury, MD, in a Norfolk “A” loamy sand soil (pH 6.3). Twelve treatments, consisting of six Brassica crops (see table), garlic clove, lemongrass, sunhemp, tomato‘Sunsugar’, watermelon ‘Sugar Baby’, and nonamended control, were arranged in a randomized complete block design in microplots. All 12 treatments were replicated three times. All crops except garlic, sunhemp and tomato were grown in agreenhouse for 4 weeks, and their above-ground biomass was collected and macerated in a blender. Sunhemp and tomato were from field grown adult plants and garlic cloves were from a grocery store. Amendments of 1.3 lbs of the maceratedplant materials or 0.65 lbs of garlic cloves were manually incorporated into the top 7.9 in. of soil on 17 Jul. Microplots were 30 in. in diameter and 24 in. deep, surrounded by fiber glass, and contained approximately 1,500 CFU/g soil of FON. Thetreated microplots were covered with two layers of black plastic film until transplanting. Five 4-wk-old greenhouse grown watermelons (‘Sugar Baby’ susceptible to Fusarium wilt) were hand transplanted in each plot on 12 Aug. Microplots that didnot receive pathogen infestation served as negative controls. All microplots were watered and fertilized as needed. Weeds were removed manually. Foliar diseases including gummy stem blight and powdery mildew were managed with BravoWeatherStik 720SC (2 pt/A) and Pristine 38WG (15 oz/A) each applied two times on alternate weeks for the final month of growth. Incidence of Fusarium wilt, the percent of plants with stunting, yellowing or wilting of one or more vines, was assessed at three (Sep 2) and five (Sep 16) weeks after transplanting.