The spotted alfalfa aphid, Therioaphis maculata Buckton, was first found in the United States about 1953 and in Alberta in 1979. This species of aphid can be more serious on alfalfa than the pea aphid because it not only sucks out the juice but it also injects a toxin into the plant. Early symptoms of spotted alfalfa aphid damage to alfalfa include vein clearing of newly emerging leaves. As feeding continues, veins may whiten and the remaining areas of the leaf turn yellow. Eventually leaves die and fail from the plant. The aphids suck juice from the phloem of leaves and stems and inject a salivary toxin that damages the plant. Young plants of susceptible cultivars are often killed by the aphid and mature plants are severely stunted and covered with a sticky honeydew secreted by the aphid. Various sooty mold fungi may develop in the honeydew. Fungal growth on the honeydew causes a reduction in hay palatability and quality

Address: 3rd fl JG ODonoghue Building, 7000 - 113 Street, Edmonton, AB T6H 5T6
Telephone: 780-643-1840
Fax: 780-643-1771
Website: http://www1.agric.gov.ab.ca/$Department/deptdocs.nsf/all/agdex728