Not only is China a big grain customer of the American farmer, but there's a new laboratory in Beijing that may help develop trade with the United States in tiny organisms that protect crops from destructive insects and weeds.

The new research operation was announced Tuesday by the Agriculture Department as a way to help find natural enemies of insects and weeds that threaten crops in the two countries.Ultimately, the exchange of "biocontrol" organisms and scientific information could help boost crop production in both China and the United States.

Orville G. Bentley, assistant secretary for science and education, said the new Sino-American Biological Control Collaborative Laboratory is located at the Chinese Academy of Agricultural Sciences.

Under a five-year agreement with the academy, three USDA scientists will go to the laboratory next May and conduct research there for six months each year. They will work in the United States the remaining six months of the year.

Richard S. Soper, biocontrol research leader in the department's Agricultural Research Service, said the Beijing laboratory will be a quarantine and research facility for exchanging potential biocontrol organisms between the two countries.

The targeted U.S. pests include: leafy spurge, a noxious rangeland weed; two water weeds, hydrilla and watermilfoil; and the Russian wheat aphid. Soper said the aphid is "the most worrisome pest." It was first spotted in the United States in 1986 and has spread rapidly to wheat-growing areas.

Pests of concern to China are: croftonweed, a weed so toxic to horses that they can't be kept on certain land; scale insects; and apple leaf mites.

Next year the Chinese academy is expected to send scientists to USDA laboratories in Fort Lauderdale, Fla.; and Buenos Aires, Argentina.

Soper said scientists at four agency laboratories in France, Italy, South Korea and Argentina are searching overseas to find biocontrols for U.S. pests. But until now, he said, scientists have not been able to easily explore most of the vast Eurasian land area.

"The new lab takes care of much of Asia that we've missed, and we're hoping we can develop similar arrangements with the Soviets," he said.

Meanwhile, the USDA also announced that private exporters have sold China an additional 400,000 metric tons of U.S. wheat at subsidized prices for shipment in January and February.

The sales, equal to about 14.7 million bushels, were handled by four companies: Cargill Inc., 190,000 tons; Central States Enterprises Inc., 40,000; Richco Grain Ltd., 40,000; and Ferruzzi USDA Inc., 130,000.

Melvin E. Sims, general sales manager for the department's Foreign Agricultural Service, said the sales were part of an authorized 1 million tons of wheat announced on Dec. 7 under the Export Enhancement Program, or EEP. About 10,000 tons also remained of an earlier EEP authorization.

WASHINGTON (AP) - The Agriculture Department has granted 13 states a total of $2.9 million to help finance mediation efforts between financially strapped farmers and their creditors.

La Verne Ausman, acting administrator of the Farmers Home Administration, said Tuesday the funds - to be matched by the states - will be used to "resolve differences between other lenders and farmers" who have loans from the USDA agency.

The money, he said, "will help make it possible for a neutral, third party mediator to cast a fresh eye on the problem. Many disputes are resolved in this manner."

For example, the FmHA and other lenders might agree to write down, or reduce, a borrower's debt or in some other way work together to help the farmer meet his obligations.

The matching grants were authorized in the Agricultural Credit Act passed by Congress last year.

States qualifying for the FmHA grants in the fiscal year that began Oct. 1 are: Alabama, $110,208; Iowa, $305,000; Kansas, $431,150; Minnesota, $500,000; Mississippi, $75,040; Montana, $75,000; Nebraska, $168,140; North Dakota, $250,000; Oklahoma, $269,870; South Dakota, $97,000; Texas, $500,000; Wisconsin, $87,440; and Wyoming, $25,000.