Phytophthora blight caused by Phytophthora capsici is one of the most economically important diseases in pepper, tomato, and cucurbit production in New Jersey. Each year for the past few decades Rutgers has evaluated new bell pepper cultivars and breeding lines for their resistance to P. capsici in field trials at the Rutgers Agricultural Research and Extension Center (RAREC) near Bridgeton, New Jersey, and in some years at research trials on farms near Vineland, NJ. The pathogen, an oomycete – ‘water mold’ is favored by warm weather and wet soils during the production season and can survive between seasons in the soil as oospores. Once found in a field, the pathogen can establish itself, and be very difficult to control even with the use of fungicides. Fortunately, in bell pepper, phytophthora blight resistant/tolerant cultivars have been commercially-available for over 20 years now and have been used extensively by bell pepper growers throughout the state. Each year, as mentioned above, Rutgers evaluates these bell peppers for their resistance to P. capsici in heavily-infested fields as well as evaluate each for their fruit quality characteristics (e.g., color, wall thickness, number of lobes, and development of ‘silvering’). Some important points to remember. The pathogen is consistently evolving because of its sexual activity (i.e., mating types and oospore production). The more researchers look into the pathogen’s genetic diversity, the more they seem to find. The pathogen can develop resistance to important fungicides. Insensitivity to mefenoxam and copper resistance have been know for a very long time. Finally, phytophthora resistant cultivars such as Paladin which have been used extensively in southern New Jersey for the past 20 years appear to be breaking down. Over the past few years a number of new phytophthora resistant/tolerant bell peppers with new sources of genetic resistance have been released and evaluated by Rutgers. Some of these new bell peppers also have varying levels of resistance to bacterial leaf spot, with one – ‘Playmaker’ having X10R resistance to bacterial leaf spot and tolerance to P. capsici. Because of the increased reports of bacterial leaf spot and copper resistance in recent years and the difficulty in controlling it alone, all bell peppers grown in NJ at some point will need to have to have X10R resistance and phytophthora blight resistance. Importantly, for organic bell pepper growers, if you have not already done so, you should be evaluating these new lines to see if they meet your needs. The easiest way to mitigate both diseases are to start with genetic resistance. Below are the bell pepper variety reports going back to 2005 for review.
For more information on recommended bell pepper cultivars please visit the Pepper Section in the 2020/2021 Mid-Atlantic Commercial Vegetable Productions Recommendations Guide.
By: Andy Wyenandt and Wesley Kline
