Evaluation of multiple biological control organisms for control of grey mold of tomato, 2006

摘要

An experiment testing different biological control organisms for the control of Botrytis grey mold of tomato was conducted at the Plant Growth Center at the Montana State University, MT. Six-week-old tomato plants grown in oasis cubes were transplanted into Coconut EZ Gro Bags (Hydro-Gardens, CO) and irrigated with a single dripper (flow rate 7.9 l/hr). The experiment used a randomized complete block design with 12 replications. Sixty bags were placed in five rows 0.6 m apart. The space of the bags within the row was also 0.6 m. The plants were kept at 24 deg C day and 16 deg C night temperatures with a 16 hr photoperiod (GE Multi-Vapor MVR1000/C/U). Treatments to control grey mold included an untreated control (plants sprayed with de-ionized water alone), Bacillus mojavensis isolate 203-7 (10e8 colony forming units/ml de-ionized water), Bacillus mycoides isolate BmJ (10e8 colony forming units/ml de-ionized water), Serenade Max (Bacillus subtilis strain QST 713, at a concentration of 2.5%), and PlantShield HC (Trichoderma harzianum strain KRL - AG2, at a rate of 3.8 g/l de-ionized water). Stem wounds caused by pruning were inoculated with a Botrytis cinerea conidia solution (10e7 conidia/ml in de-ionized water supplemented with 62.5 mM KH2PO4 and 5.5 mM Glucose, sprayed to run off). Inoculation was followed by overhead mist-irrigation to increase the humidity and to establish Botrytis stem canker infection. The mist-irrigation was applied every night for 12 hr in 30 min intervals for 30 sec duration. The first foliar application of treatments was conducted at 22 Nov 05 and successive sprays were applied weekly through 21 Feb 06. Yield data were collected over several weeks by harvesting and weighing ripe tomatoes until 4 Mar 06. Disease data for the leaf infections were collected on 11 Feb 06 and 28 Feb 06 by following rating scale (0-5) to estimate the percentage of leaf area covered by leasons on 10 individual leaves per plant: 0 = no lesions, 1 = multiple single lesions (> 10%), 2 = 25%, 3 = 50%, 4 = 75%, 5 = whole leaf covered (100%). Botrytis stem canker ratings were conducted at a weekly interval starting on 3 Jan 06 until 31 Jan 06, and at 14 Feb 06 and 28 Feb 06 by estimating the disease progress using following rating scale: 0 = no stem canker, 1 = lesion present, 2 = water soaking of lesion, 3 = water soaking extends into stem tissue, 4 = stem infected, 5 = stem girdled by canker.