100 years of Fungicide Protection Against Brown Rot of Stone Fruit

Brown Rot on Peach

Brown Rot on Peach

The brown rot fungus infects all the acres of cherries, peaches and nectarines in the U. S. Ash-gray masses of millions of spores appear on the fruit and the fruit becomes completely rotten and soft within a few days. Brown rot caused substantial fruit losses before the development of fungicides. Most peach growers expected to lose 50-75% of their crop. With the development of a finely-powdered sulfur fungicide about 1912, stone fruit growers began widespread spraying to control brown rot. This spraying has continued to this day.

“Who does not love the delicious taste of fresh peaches, nectarines, plums, apricots, or cherries? Because of their popularity, stone fruits are grown all over the world, but it is not only consumers who like these tasty fruits. Some fungi have specialized in infecting and colonizing stone fruits wherever they are grown. 

There are ways to reduce disease pressure in commercial orchards, including the removal of fruit mummies from the tree canopy, pruning out cankers and removal of wild plums surrounding orchards. However, these measures do not prevent brown rot disease, and growers are still dependent on the application of fungicides for blossom blight and pre- and postharvest disease management.”

Authors: Schnabel, G., et al.
Affiliation: Clemson University.
Title: Sustainable brown rot management of peaches in the southeastern United States.
Source: Outlooks on Pest Management. 2010. October. Pgs. 208-211.

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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.

Pecan Weevils Feast on Pecans in Orchards

Pecan Weevil Larva

Pecan Weevil Larva

Pecan Weevil Adult

Pecan Weevil Adult

The pecan weevil is a late season nut pest that feeds only on pecans and hickory. The female drills a hole in the nut with her snout and places one to four fertilized eggs within the kernel. The pecan weevil larvae are creamy, white legless grubs with soft fleshy bodies. Heavy populations of weevils can destroy all nuts on a tree.

“The pecan weevil is a major pest of pecans throughout the southeastern United States, as well as portions of Texas and Oklahoma. … Adults emerge from soil in late July-August to feed on and oviposit in developing nuts. Larval development is completed within the ripening kernel of the nut.”

“Current control recommendations for pecan weevil consist mainly of aboveground applications of chemical insecticides (e.g., carbaryl) to suppress adults. Application of chemical insecticides is recommended every 7-10 days during peak weevil emergence (generally up to at least a 6 week period).”

Authors: D.I. Shapiro-Ilan1, W.A. Gardner2, T.E. Cottrell1, R. W. Behle3 and B.W. Wood1

Affiliation:
1USDA-ARS, Southeastern Fruit and Tree Nut Research Laboratoy, Byron, GA; 2Department of Entomology, University of Georgia, Griffin, GA; 3USDA-ARS-NCAUR, Peoria, IL
Title: Comparison of application methods for suppressing the pecan weevil (Coleoptera: Curculionidae) with Beauveria bassiana under field conditions.
Publication: Environmental Entomology. 2008. 37(1):162-171.