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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Consumers Want Perfect Avocados: Growers Must Spray

Infected Avocados

Avocado Thrip Fruit Scarring

Historically, the production of avocados in California required little usage of insecticides. Avocado pests were kept under commercially acceptable control by a variety of beneficial organisms. This situation changed in 1996 with the appearance of avocado thrips which feed on the surface of the fruit. Feeding scars develop while the flesh of the fruit is a healthy green. Even partial fruit scarring results in downgrading of fruit in packinghouses because of cosmetic damage unacceptable to consumers .

“The California avocado industry is under increasing threat from the introduction of arthropod pests. The avocado thrips, was first detected in California avocado groves in June 1996, and it has since spread to most of the major production areas within the state where it has become the primary insect pest. The main source of economic loss arises from feeding damage that causes scarring of immature fruit, leading to a reduction in fruit quality at harvest.

In California avocado groves, the use of foliar insecticides is the predominant tactic adopted by growers for the management of arthropod pests, including the avocado thrips. Aerial applications by helicopter are needed for the majority of California avocado groves because most are grown on steep hillsides.”

Author: Byrne, F. J., et al.
Affiliation: University of California
Title: Field evaluation of systemic imidacloprid for the management of avocado thrips and avocado lace bug in California avocado groves.
Source: Pest Management Science. 2010. 66:1129-1136.

Fly Eggs in Fruit? Insecticides Are the Only Option

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Serrated Egg Layer Drosophila

berries

Blueberries: Drosophila Infestation (Right)

The invasive spotted wing drosophila fly came into the US from Asia in 2008 and has spread throughout the US. The fly prefers softer, sweeter ripe fruit- cherries, raspberries, blueberries,blackberries and strawberries. The female flies use saw-like blades on their abdomens to cut through the skin of ripe fruit and lay their eggs inside. The eggs hatch into worms that feed on the flesh of the fruit – ruining the fruit for sale. Insecticides are currently the only option for drosophila control and growers throughout the US are being advised to spray.

“The spotted wing drosophila, a tiny fly that can take a big bite of orchards and gardens, has gradually been making its way across the country from the West Coast and has discovered the summer bounty in the Granite State is much to its liking, according to Dr. Alan Eaton, an entomologist with the University of New Hampshire.

If the flies show up around the time the fruit ripens, the farmers have to immediately spray to kill them off, Eaton said. There are both standard and organic remedies available, he said, but spraying is vital to saving crops. “We’ve had a few growers who weren’t listening to us and their entire crops were wiped out,” said Eaton.”

Author: Nancy Bean Foster
Affiliation: Union Leader Correspondent
Title: Fruit farmers on guard for new pest
Source: Union Leader. August 26, 2013. Available at: http://www.unionleader.com/article/20130827/NEWHAMPSHIRE07/130829419?dm_i=1ANQ,1T79M,6LPYOS,6H5RF,1

The Dilemma of Insect Fragments in Processed Tomatoes

Tomato Fruitworm Damage

Tomato Fruitworm Damage

The tomato fruitworm is the most serious insect pest of tomatoes in the US, feeding on fruit and contaminating it with insect parts, excrement and decay-causing organisms. Interest in spraying insecticides to control the fruitworm was accelerated in the 1930s by the finding of insect fragments in canned products, which were seized and destroyed as adulterated foods by the FDA. Today, insecticides are used to prevent widespread insect damage to tomatoes and tomato shipments for processing are rejected if more than 2% damage is found. Therein is the dilemma. If the standard was relaxed (say to 4%), tomato growers could probably make one less insecticide spray. However, consumers may not want more insect fragments in canned tomatoes and may actually want a tighter standard which would result in more insecticide sprays.

“All loads of processing tomatoes in California are evaluated by inspectors from the Processing Tomato Advisory Board, a marketing order, under the direction of supervising inspectors from the California Department of Food and Agriculture. A load of processing tomatoes is rejected if 2% or more of the tomatoes by weight have a worm or excreta in the flesh of the tomato.

The damage tolerance acceptable to consumers and industry could be changed accordingly. Increasing the tolerance might be expected to result in a reduced number of insecticide applications when used in conjunction with a careful monitoring program.

A reduction in the tolerance might also be considered, arguing that consumers would not tolerate even the present level of insect fragments which, as our results indicate, is possible to have in the final product.”

Authors: Zalom, F. G., and A. Jones.
Affiliation: Department of Entomology, University of California, Davis
Title: insect fragments in processed tomatoes
Source: Journal of Economic Entomology. February, 1994. 87[1]:181-186.

Chilean Apple Growers Must Use Insecticides to Control Quarantine Pests

Codling Moth Frass

Codling Moth Frass

Chile is a major exporter of apples to other Latin American and Asian countries. Some of these countries do not have populations of the codling moth and they want to keep the insect out. Codling moth is present in Chilean apple orchards which means that growers must spray insecticides to assure that their export fruit shipments will not be rejected.

“Regular applications of insecticides have been the main management practice against codling moth in Chile. … Pest management in Chilean apple orchards with fruit grown for export is dependent on intensive pesticide use, mainly because of strong quarantine restrictions toward the codling moth from Asian and Latin America countries. In this production scenario, even low levels of fruit damage at harvest (<0.5%) are a major concern for growers. To avoid quarantine rejection of exports, an increase in the frequency of insecticide sprays has been observed.”

Authors: E. Fuentes-Contreras1, M. Reyes2, W. Barros1 and B. Sauphanor2

Affiliation:
1Department de Producción Agrícola, Universidad de Talca, Talca, Chile; 2PSH-Ecologie de la Production Intégrée, INRA Site Agroparc, Avignon Cedex, France
Title: Evaluation of azinphos-methyl resistance and activity of detoxifying enzymes in codling moth (Lepidoptera: Tortricidae) from central Chile.
Publication: Journal of Economic Entomology. 2007. 100(2):551-556.

National Academy of Sciences Credits Pesticides with Improving American Diet

Americans take for granted a plentiful, inexpensive daily supply of fruit and vegetables. This bounty has come about due to increased production throughout the county as a result of pesticide use – a point made by the National Academy of Science…

“Pesticides are used widely in agriculture in the United States. When effectively applied, pesticides can kill or control pests, including weeds, insects, fungi, bacteria, and rodents. Chemical pest control has contributed to dramatic increases in yields for most major fruit and vegetable crops. Its use has led to substantial improvements over the past 40 years in the quantity and variety of the U.S. diet and thus in the health of the public.

Authors: National Research Council
Affiliation: National Academy of Sciences
Publication: Pesticides in the Diets of Infants and Children. 1993. National Academy Press, Washington, DC.