Biofumigation with Fresh Manure or Brassicaceae Residuals could be a Promising Methyl Bromide Alternative in Head Lettuce Production

The current study investigates the natural alternatives of methyl bromide on head lettuce plants grown in greenhouse. Lettuce (Lactuca sativa L.) seedlings (cv. “Big Bell”) were treated with six different MBr alternatives which are, Biofumigation with fresh cow manure, fresh chicken manure, or Brassicaceae residuals plus Bio-Compost application (using disease suppressive compost) in comparison with chemical control with one of MBr chemical alternatives (Basamid) and finally negative control (which is the standard farmer treatment). Despite that chemical control with Basamid recorded the highest survival rate, biofumigation with fresh chicken manure gave the best head length, diameter, fresh weight, dry weight, total and marketable yield. Also, highest head quality characteristics such as TSS, SPAD reading, and nitrogen content were recorded with biofumigation with fresh chicken manure. Regardless of the superiority of Biofumigation with fresh chicken manure, Biofumigation with fresh cow manure or Brassicaceae residuals showed a better vegetative growth and quality parameters than farmer treatment (control), and they had significantly less effect than chemical control treatment. Bio-Compost fortified with Trichoderma harzianum and Bacillus subtilis (disease suppressive compost) recorded survival rate similar to biofumigation treatments but were significantly lower than chemical control treatment. Bio-Compost treatment did not result in a good result regarding total and marketable yield head fresh and dry weight. There was no detected significant effect of the studied treatments on stem diameter, L‑ascorbic acid (vitamin C), phosphorus and potassium content