Los Banos Rotary Club History
Dr. Ray Smith Explains Problems Of Alfalfa Aphid

We can live with the alfalfa aphid, but we are not going to like it, stated Dr. Ray Smith, noted entomologist with the University of California at Davis, in a talk before the local Rotary Club Tuesday noon.

Declaring the alfalfa aphid to be the most serious pest problem that California has faced since the memorable cottony cushion scale hit the citrus industry in 1888, Smith predicted that by next summer the aphid will be found in practically every alfalfa field in the state.

In two years the aphid has swept north through California without any natural enemy to check it. Effective sprays are, however, available that provides excellent kills at a cost of from $1.00 to $2.00 per acre for material or total cost of $3 to $4 an acre per application. The problem is multiplied by the fact the aphid is a great traveler, both by wing and by piggy-back, riding on trucks, cars, clinging to the hair of animals, trouser cuffs and clothing of field workers, etc, so that one untreated field in any area can quickly re-infest large acreages nearby.

He said that University entomologists and the State Department of Health have learned much about the pest in the past two years, and said further studies are underway. However, most authorities today predict that the pest will never be completely wiped out, due to their rapidity of movement and terrific reproduction capacity.

Dr. Smith showed colored slides to better describe the pest and illustrate the damage that occurs in infested fields. For the immediate future, he said, the most important thing is for all farmers to realize the seriousness of the pest, and work closely together to control all infested fields. Even this, he said, is only partially effective, citing an instance near Bakersfield last summer when 100,000 acres of alfalfa some fields several times to secure were treated at one time, and a maximum kill, yet because a few isolated patches were overlooked, widespread re-infestation soon occurred. However, with close cooperation of all farmers, it is believed that good control can be maintained with not more than one spray application per cutting through the year.
Future relief for this immediate area, he said, will be found in the next two or three years, as the new aphid resistant Lahanton variety of alfalfa is planted to replace present varieties. Sufficient seed for all planned Lahanton plantings can not be made for at least two years.

Another possibility, he said, is the importation from Europe of natural insects that feed on the alfalfa aphid but in themselves are not harmful to crops. Experimental work on this phase is now underway, but it is too early to anticipate any degree of success that might be attained.

"However," Dr. Smith concluded, "California agriculture has faced similar problems before and came through successfully. I am sure we can whip this problem also."

Young alfalfa of the present varieties, he stated, is especially vulnerable to the aphid, one of the insects sometimes being enough to completely kill a very young alfalfa plant.

October 14, 1955

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