Document Type : Original Article
Authors
1
Central Lab Organic Agriculture, A.R.C., Giza, Egypt
2
Vegetables Res. Dept., Hort. Res. Inst., A.R.C., Giza, Egypt
Abstract
The objective of this work is to study the effect of three different bio-agents, i.e. Trichoderma harzianum (T. harzianum), Bacillus subtilis (B. subtilis) and Streptomyces griseus (S. griseus), in addition to two natural salts (potassium silicate and mono-potassium phosphate, MKP) and two different plant densities of pepper on powdery mildew (PM) incidence, severity, some horticultural characteristics and yield. Original high tunnel greenhouse located at Kaha Research Station, Qalyubia governorate was used. Data revealed that, low planting density led to decrease of PM disease incidence and severity when compared with high planting density. Increase in pepper growth in terms of plant height, number of leaves, number of branches, leaf area, fresh and dry weights per plant was noticed when low planting density was used compared with high planting density. Fruit quality, i.e. fruit weight, length, diameter, flesh thickness and chemical characteristics were also increased with low density. The highest yield characteristics, i.e. early yield, number of fruits per plant and total yield were increased with low planting density. Regarding biological control and natural salts, data revealed that the highest reduction in disease incidence was obtained when B. subtilis was used. Disease severity was also recorded and T. harzianum stand as the most effective treatment in reducing disease severity. Maximum values of the vegetative growth characteristics, fruit quality and yield were recorded when foliar application with MKP followed by the application with B. subtilis. Laboratory analysis for treated plants showed that disease control was positively correlated with amount of phenols and sugars in leaves. Interaction between low planting density with B. subtilis or MKP treatment reduced PM disease incidence and severity. Significant effect on vegetative growth characteristics, early yield, number of fruits per plant and yield was recorded with this interaction.
Keywords
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