Have you ever driven by Sumida Farm and wondered why we have to water watercress? It would make sense that a crop that relies on fresh water would need additional irrigation, but our aerial sprinkler system is actually designed for pest control!
Pests are one of the most common enemies to farms, especially in Hawai’i. For watercress and other leafy greens, the diamondback moth is one of the worst offenders. These destructive pests lay eggs on leafy greens and feast on the leaves, destroying whole crops when uncontrolled. In 1982, the watercress industry was nearly wiped out when the diamondback moth became resistant to insecticides and all watercress farmers on Oahu experienced total crop failure.
Sumida Farm Agronomist, John McHugh, was getting his Masters Degree in Horticulture at UH Manoa when he researched whether a sprinkler system could provide a cooler, more favorable climate for watercress. Research conducted in 1978-80 showed a 56% increase in watercress production by using intermittent sprinkling throughout the day. Another benefit observed was a decrease in moth activity. John discovered the diamondback moth was unable to attach its eggs to the watercress leaves when the leaves were wet.
Second generation Sumida Farm President, Masaru Sumida, installed sprinklers throughout the farm, and found immediate success with reducing the diamondback moth. The information was shared with other local farms and revived the leafy greens industry.
To this day, the combination of our aerial sprinklers and natural enemies like damselflies and lady bugs serve as our main form of pest control throughout the farm.
Sumida Farm is forever grateful to John McHugh for his dedication and career focus helping to ensure we are able to cultivate the world’s best watercress!