Cultivation in Rice Straw and Other Natural Treatments as an Eco-Friendly Methyl Bromide Alternative in Head Lettuce Production

The present investigation deals with finding natural alternatives to methyl bromide in order to reduce its environmental damage in greenhouse grown head lettuce plants (lactuca sativa L.) seedlings (cv. ‘Big Bell’). Five treatments were evaluated to find a better natural methyl bromide (MBr) alternative which are, cultivation in local materials using rice straw bales as a cultivation medium, using of hot water injection into soil to control soil pathogens, using a mix of Trichoderma harzianum and Bacillus subtilis as a biological control treatment, in comparison with chemical control with one of MBr chemical alternatives (Basamid®) and Control (farmer treatment). Cultivation in rice straw was superior in head diameter, head length, head fresh weight and head dry weight than all the other treatments. While chemical alternative was advanced in only head total soluble solids content (TSS) and chlorophyll content. Both chemical alternative (Basamid) and cultivation in rice straw had the highest values of plant survival rate, head potassium content, and both total and marketable yield (Kg/m²) followed by the other natural MBr alternatives which also had a significant positive effect on plant vegetative growth in comparison with control treatment (farmer treatment). Also, there was no detected significant effect of the studied treatments on stem diameter, L‑ascorbic acid (vitamin C), nitrogen and phosphorus content