The lychee, also known as litchi, grows on a tropical and subtropical fruit tree native to southern China, Taiwan, Bangladesh and Southeast Asia, and now grown in many parts of the world. The lychee has a history and cultivation going back as far as 2000 BC. In the 1st century, fresh lychees were in such demand at the Imperial Court that a special courier service with fast horses would bring the fresh fruit from Guangdong. It was first introduced to the west in 1782. The fresh fruit has a delicate, whitish pulp with a floral smell and a fragrant, sweet flavor. Dried lychee are often called lychee nuts, though, of course, they are not a real nut. Litchi downy mildew is a devastating disease of litchi plants in China. Control of litchi downy mildew requires numerous fungicide applications.
“Litchi (Litchi chinensis Sonn.) is a tropical and subtropical fruit of high commercial value. Most litchi fruits are produced in China, India and Vietnam. In 2001, the world litchi production was approximately two million tons, and approximately 1.26 million tons were produced in China… However, the fruits are very susceptible to many diseases with significant losses in quality and yield. One of the most prevalent diseases is litchi downy blight caused by the peronosporomycete Peronophythora litchii.
P. litchii damages fruit, panicles and new shoots, causing panicle rot and withering, as well as watery brown spots on fruits which later produce snowy mildew. More than 60% of commercial losses have been reported after successive rainy and overcast days in the growing season.
The primary components of all commercial management programmes for this disease are applications of organic and/or inorganic fungicides.”
Authors: Wang, H., et al.
Affiliation: College of Plant Protection, Nanjing Agricultural University, China.
Title: Fungicide effectiveness during the various developmental stages of Peronophythora litchii in vitro
Source: Journal of Phytopathology. 2009. 157:407-412.
Most of the 95 strawberry farm stands in and around the Sacramento region are owned and operated by Mien and Hmong refugees from Laos, a small country in Southeast Asia that neighbors Vietnam. When the U.S. left Southeast Asia in 1975, hundreds of thousands of Hmong and Mien fled to the U.S. Most of the refugees were farmers in Laos and turned to farming in the U.S. Most growers lease small plots of land and grow strawberries for sale. A group of University of California researchers received a USDA grant to work with these refugee farmers. It became apparent that fungicide use is a critical element in improving the economic viability of the refugee farmers.
“Sacramento County Southeast Asian strawberry growers are very limited-resource growers who sell almost strictly at their roadside stands. UC Cooperative Extension has been working with these growers for 14 years and holding an annual meeting every March. This year’s meeting was held on March 24, 2010, and was supported by the California Strawberry Commission… A total of 52 growers attended the meeting, including several from nearby counties. In 2009-10, we received funding from the USDA to work with Sacramento County growers on food safety education, pest and nutrient management education, variety trials and market expansion.
Two of the most challenging and consistent pest problems facing Southeast Asian strawberry growers are spider mites and fruit rot… Fungicides are rarely used, and botrytis fruit rot caused by pre-Mother’s Day 2009 rains decimated all growers’ crops just before the busiest time of year. A leading grower did spray fungicide and estimated that he saved 50% of his crop.
Four treatments were compared to evaluate their effectiveness in reducing fruit rot, as well as their effects on yield.
The amount of rot per plant in the tunnel and fungicide treatments was significantly less than that of the untreated control.”
Author: Ingels, C.
Affiliation: UC Cooperative Extension
Title: Spider mite and botrytis rot trials
Source: California Strawberry Commission Annual Production Research Report. 2009-2010 Research Projects. Pgs. 99-103