Lincoln University and the University of Missouri have joined with Purdue University to provide a computer-based spray advisory system, MELCAST (MELon disease forCASTer), that allows melon growers to base their spraying on the weather. Otherwise, spraying occurs after a certain number of days.
MELCAST informs growers when to spray fungicides for three important watermelon and muskmelon diseases: alternaria leaf blight, gummy stem blight and anthracnose.
MELCAST was developed by Dr. Richard Latin, Purdue University plant pathologist, in 1996. Since then, it has been used in the major watermelon-growing areas of the U.S.
I have been supporting four to six MELCAST sites in Missouri since 2013. Farms on those six sites or within a 25-mile radius can use MELCAST. Three of the sites are in southeast Missouri at Sikeston, Clarkton and Hornersville.
Donald Horvarth used MELCAST on his watermelon fields in Hornersville, Mo., in 2016 with help from Lincoln University Cooperative Extension. He was “happy that MELCAST saved (him) two to three fungicide sprays on one field,” as he told me during a farm visit early in March. Horvarth reduced his production costs, including all the money, time and resources saved by not having to spray. Overall, he is more likely to produce watermelons with less fungicide, so he is helping the environment by using less fungicide.
A study of MELCAST was done from 2013-15 at Lincoln University’s George Washington Carver Farm in Jefferson City, Mo. It resulted in one to two spray savings per season. Even with this reduction, fewer diseases occurred than most growers contended with in southeast Missouri during the same time.
MELCAST saves fungicide sprays for growers and helps growers make informed decisions about the exact time to intervene. When the weather is warm and humid, sprays might occur every five to six days, but when it is windy and dry, the interval can extend up to 14 days. Based on his experience with the benefits of MELCAST, Horvarth plans to continue using it during the 2017 growing season.
Dr. Zelalem Mersha is an assistant professor and state Extension specialist with Lincoln University Cooperative Extension.