Preliminary report on resistance of alfalfa varieties to pea aphids, Illinoia pisi (Kalt)
1935
Painter, R.H. | Grandfield, C.O.
An opportunity to study the reaction of different alfalfa varieties to pea aphids presented itself in the spring of 1934 in an alfalfa variety test being conducted on the agronomy farm at the Kansas Agricultural Experiment Station. The most severe outbreak of pea aphids on record for eastern Kansas occurred at that time, bottom fields being almost invariably heavily infested, while on the uplands the infestations were lighter. The unusual feature of the infestation was that the fields were rather uniformly infested. The large number of aphids resulted in a stunting and yellowing of infested fields that brought into sharp relief differences between individual plants. In a 4-year-old alfalfa variety test consisting of 36 varieties, the number of plants showing no injury varied greatly enough to make a noticeable difference in the appearance of the plats. Examination of these plants showed that they were infested by fewer aphids than other plants indicating they may be different from others in the variety.
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