Enhancement of Purple Blotch Disease of Onion by Thrips Injury
The role of Thrips tabaci injury to onion in the invasion of Alternaria porri (Ellis) and rate of purple blotch disease development was determined. In the absence of thrips injury, older leaves were more susceptible to infection by A. porri. Plant growth was negatively correlated to thrips injury. Thrips-infested plants developed more and larger A. porri lesions that coalesced as plants matured. The intra-plant distribution of purple blotch infection shifted to younger leaves as a result of thrips damage and more tissue was killed by thrips in the presence of purple blotch.
KeywordsLeaf Area Young Leave Leaf Length Total Leaf Area Estimate Leaf Area
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