Bio-based and Reduced-Risk Strategies for the Management of Phytophthora Blight and Root Rot of Pepper

Abstract

Phytophthora blight and root rot caused by Phytophthora capsici affects several solanaceous and cucurbit hosts worldwide. The disease has become a constraint in cultivation of chili pepper in China and is an emerging problem in Canada and the USA affecting pepper, tomato, cucumber, and other cucurbits. Several bio-based approaches such as biofungicides; soil amendments of rapeseed meal, composts, and manures; soil solarization; grafting; and reduced-risk chemicals have been investigated for the management of Phytophthora blight and root rot of pepper. The biocontrol potential of fungal antagonists such as Penicillium striatisporum Pst10, Trichoderma harzianum, and Trichoderma hamatum 382 and bacterial antagonists such as Bacillus amyloliquefaciens BS211, Pseudomonas corrugata, and other Pseudomonas and Bacillus strains was shown for suppression of pathogen growth and disease. Soil amendment of rapeseed meal, manures, and composts also provided suppression of Phytophthora blight and root rot under greenhouse and field conditions. Some combinations of biocontrol agents and soil amendments provided enhanced disease control. Soil solarization can be very effective in reducing pathogen inoculum from the top 10-cm layer of soil, but this strategy may be only effective in countries where summer months are very hot. Anaerobic soil disinfestation using wheat straw as the carbon source followed by flooding for 2–3 weeks reduced pathogen populations in soil and also disease incidence on pepper. Reduced-risk chemicals such as phosphonates and Actigard and grafting of resistant rootstocks also provided disease control and offer additional sustainable methods for the management of Phytophthora blight and root rot of pepper. Integration of various management strategies may be more effective for managing disease problems such as Phytophthora blight and root rot.