Rice Insect Pest Invades the World from the USA

Rice Water Weevil Larva

Rice Water Weevil Larva

The home of the rice water weevil is the southeastern US where the species feeds on
grasses in swampy areas. When rice plants were introduced into America, the
insect quickly found this new grass plant to its liking and has been feeding on
rice ever since. The weevils move into rice fields every year from nearby woods
and clumps of grass. Farmers have used insecticides since 1950 to control the
weevil populations in rice fields. The rice water weevil has spread from the
southeastern US to Louisiana, Texas, California, Japan, China and Italy where
it would decrease rice production without insecticide sprays.

“The rice water weevil, Lissorhoptrus oryzophilus, is the most destructive insect pest of rice in the United States. The insect is native to the southeastern United States but has, over the past 60 years, invaded important rice-growing areas in California, Asia and Europe and thus poses a global threat to rice production.

Small-plot research and sampling of commercial fields indicate yield losses from the rice water weevil would likely exceed 10% in many areas if no insecticides are used.”

Authors: Stout, M. J., et al.
Affiliations: Department of Entomology, Louisiana State University.
Title: The influence of rice plant age on susceptibility to the rice water weevil, Lissorhoptrus oryzophilus.
Source: Journal of Applied Entomology. 2013. 137:241-248.

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Southern California Vineyards Recover Thanks to Insecticide Applications

Grapevines Destroyed in 1999

Grapevines Destroyed in 1999

Temecula Today

Temecula Today

In 1999, about one-third of the vineyards in Temecula Valley, Riverside County, California were destroyed due to Pierce’s Disease which is caused by a bacteria transmitted to grapevines by an insect-the glassy winged sharpshooter. The disease seemed destined to spread throughout Southern California. However, research demonstrated that a carefully-timed insecticide application would prevent the sharpshooter from transmitting the disease to grapevines. As a result of this insecticide use, the wine grape industry in Southern California has recovered and is prospering.

“Twelve years ago a Pierce’s disease epidemic in Southern California wine grapes prompted a multi-pronged local, state and federal attack to contain the disease spread and find a cure or treatment.

Riverside County agriculture officials declared a local emergency in 1999 and 300 acres of Temecula wine grape vines were destroyed after they were found to be infested with the glassy winged sharpshooter.

Emergencies were declared, a task force was formed, and in 2000 $22.3 million in federal financial assistance was secured to reduce pest infestations and support research.

Research found that the Southern California epidemics were almost entirely the result of vine-to-vine transmission…. A protocol of applying one carefully timed application of a persistent systemic insecticide such as imidacloprid virtually eliminates the vine-to-vine spread.

Ben Drake is a Temecula-area wine grape grower and vineyard manager who began seeing problems from PD in the Temecula Valley as early as 1997.

We’ve found that if we apply (imidacloprid) at the middle to the end of May, before the sharpshooter moves out of the citrus and goes into the vineyards, we get levels of the material into the plant high enough that when the sharpshooter flies over from the citrus groves to try it, they just fly back where they came from. Or, if they feed long enough, it will kill them.

But just look at the Temecula Valley now to understand what’s changed: From 12 wineries in 1999, the Temecula Valley Winegrowers Association website today lists more than 50 growers and 34 wineries…. A thriving agritourism industry has developed…. Existing wineries are expanding and new ones are under construction or in planning phases.”

Author: Christine Thompson
Affiliation: Reporter
Title: Grape growers urged to remain vigilant against sharpshooter pest
Source: Western Farm Press. 2011-12-12. Available at: http://westernfarmpress.com/grapes/grape-growers-urged-remain-vigilant-against-sharpshooter-pest

Japanese Consumers Have High Standards for Rice Quality Making Insecticide Use Necessary

Damaged Rice

Damaged Rice

Rice Bug

Rice Bug

The feeding of rice bugs on rice plants results in black marks on the rice grains. Japanese consumers demand perfect rice, which means that farmers must prevent the insects from feeding.

“A complex of Hemiptera, commonly referred to as rice bugs, are considered to be important insect pests in rice-growing regions of the world. Many species of Hemiptera, from families including Alydidae, Pentatomidae, Coreidae, and Miridae, have been reported as rice bugs.”

“Rice bugs cause yield loss, decrease the quality of grain, and reduce the germination rate. Among these problems, decrease in the quality of grain is considered to be the most important problem in Japanese rice. Infestations cause brown or black marks on the grain. Contamination of as little as 0.1% of such stained grain has reduced commercial value according to Japanese rice quality regulations, and thus the economic injury level is very low. This has led rice farmers to a dependence on insecticide use for rice bug control.”

Authors: H. Takeuchi1,2 and T. Watanabe1
Affiliation: 1Department of Entomology and Nematology, National Agricultural Research Center, Tsukuba, Japan; 2National Agricultural Research Center for Kyushu Okinawa Region, Kumamoto, Japan.
Title: Mortality factors of eggs of Leptocorisa chinensis (Hemiptera: Alydidae) in rice fields.
Publication: Journal of Economic Entomology. 2006. 99(2):366-372.

Japan’s Most Popular Green Tea Variety Depends on Fungicides

In the 1970s, a new high-yielding green tea variety – Yabukita – was introduced in Japan and has been wildly popular because of quality attributes that Japanese tea drinkers favor, including the characteristic “umami” savory taste. This one-cultivar industry led to prevalent and frequent outbreaks of tea plant diseases which has resulted in a dependence on regular fungicide applications.

“Tea is one of the most important cash crops in the warm southwest areas of Japan. The green tea cultivar ‘Yabukita’ has been cultivated since the 1970s and grown in about 75% of all tea fields in Japan. Using a monoculture cultivation system, new Yabukita tea shoots can be harvested synchronously, producing green tea of consistent quality. However, this system has resulted in severe pest problems such as outbreaks of tea anthracnose … and tea gray blight … Therefore, repeated spraying of fungicides is needed to protect tea plants against both the diseases for each tea crop.”

Authors: K. Yoshida, A. Ogino, K. Yamada and R. Sonoda
Affiliation: National Institute of Vegetable and Tea Science
Title: Induction of disease resistance in tea (Camellia sinensis L.) by plant activators.
Publication: Japan Agricultural Research Quarterly. 44(4):391-398.

Herbicides Eliminated Inhumane Drudgery of Weeding Rice

For centuries, rice fields in Japan were weeded by millions of people who spent their summers in the hot, humid, muddy fields working in a stooped position that could cause permanent back pain and damage. Herbicides freed people from this drudgery…

“For a long time before 1949, all weeding in rice fields had to be done by man-power. It was so severe and cruel labor for farmers. Modernized weeding, that is with the use of herbicides, has saved them from these physical and mental pains.”

“Herbicide has brought a great benefit to rice cultivation… in liberation from the inhumane physical and mental pains of farmers during serious weeding labor in hot, humid and muddy paddy fields. …for the ‘perfect’ hand weeding we need 506 hours/hectare, which can be calculated as the work of 1.89 million people every day for 60 days in summer all over Japan. It is not practical in the present status in this country.”

Author: Shooichi Matsunaka
Affiliation: Former President of the International Weed Science Society
Title: Historical review of rice herbicides in Japan
Publication: Weed Biology and Management. 2001. 1:10-14.