
Potential Chocolate Shortage May Be Foiled
by Beneficial FungiBy Hank Becker October 25, 1999WASHINGTON, Oct. 25--U.S. Department
of Agriculture scientists are working with a team of international experts
to save the chocolate crop from three pathogenic fungi,
Agricultural Research ServiceAdministrator Floyd Horn said today. Chocolate is produced from the beans of
the tropical cacao tree, Theobroma cacao. "Three major fungal diseases can make cacao beans inedible or
unusable," said Horn. "But scientists at USDA's Agricultural Research
Service have identified and are testing beneficial fungi that control the bad
fungi." The international effort coordinated by ARS includes the
American Cocoa Research Institute,
McLean, Va.; M&M Mars, Inc., Hackettstown,
N.J.; and several international research groups. ARS is the chief research
agency of the U.S. Department of Agriculture. Fungal diseases--black pod rot, frosty pod rot and witches' broom--have
caused severe yield losses to the cacao bean crop, which totaled almost 3
million tons in 1999. "The diseases cause economic hardship for 5 to 6
million small farmers in South America, Africa and Asia," Horn said.
"Plus, few people realize that transforming cacao beans into chocolate is
among the largest industries in support of U.S. agriculture." For every dollar of U.S. cacao imports, about $1.50 in other agricultural
commodities is used to make chocolate confections, according to the American
Cocoa Research Institute. "The fungus problem threatens the long-term health of the world's
chocolate industry. But the research provides hope for small cacao farmers--and
environmentalists concerned about the loss of cacao agroforests," Horn
said. Brazil annually exports about $100 million worth of cacao beans to the U.S.
and traditionally has been the top South American cacao exporter. But witches'
broom and other problems have made Brazil slip to eighth place in the past 5
years, according to John B. Lunde, director of international environmental
programs for M&M Mars. To help solve the fungal problems, plant pathologist Robert D. Lumsden at
ARS' Biocontrol of Plant Diseases Laboratory, Beltsville, Md., is working with
M&M Mars microbiologist Prakash K. Hebbar as part of a cooperative research
project in which 10 national and international research institutes participate.
Several years ago, Lumsden and colleagues at the Beltsville lab developed
methods to mass-produce beneficial fungi to combat plant disease. Their earlier
research on the Trichoderma virens fungus led to its development as a
commercial product, SoilGard, marketed to control several diseases of
greenhouse, fruit and vegetable crops. "Chemical controls for the fungi that attack cacao beans don't work
very well and are expensive," Lumsden noted. "But cultivars tolerant
of the fungal diseases are largely unidentified or have not been propagated in
sufficient quantities." In the first year of field trials in Peru, the scientists used simple garden
sprayers to spray a mix of five different strains of locally isolated
Trichoderma on flowers and pods of trees infected with frosty-pod
disease, Peru's main cacao disease. "The mix of five biocontrol strains
increased pod yields even more than strains used alone," Lumsden said. At the Mars' Almirante Cocoa Research Center in Brazil, researchers are
trying two new species of Brazilian isolated Trichoderma in lab trials
and small field tests. "One species, called T. stromaticum, reduced
pod infection by the witches' broom fungus by 31 percent," said Lumsden.
ARS scientists are investigating how this Trichoderma species works and
seek more economical methods for mass-producing it. "This would make it
easier and more cost-effective for small farmers to use," he said. Lumsden said the researchers' goal is to identify natural controls for use
in integrated pest management systems. The IPM systems would also use
fungus-resistant cacao lines and cultural practices that encourage sustainable
cacao cultivation in the natural forest ecosystem. Each year, U.S. chocolate manufacturers use about 250,000 tons of dry milk,
400,000 tons of sugar and 350,000 tons of peanuts. In 1997, the U.S. industry
used more than $3 billion worth of these and other U.S. agricultural products.
The U.S. exports over $600 million worth of chocolate products a year. A story about the research will appear in the November issue of ARS' Agricultural Research magazine. Scientific contact: Robert D. Lumsden, ARS
Biocontrol of Plant
Diseases Laboratory, Beltsville, Md., phone (301) 504-5682, fax (301)
504-5968, [email protected] and
[email protected]. U.S. Department of Agriculture | |