. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 14 BULLETIN 112, U. S. DEPARTMENT OP AGRICULTURE. avence at La Fayette, Ind., and Washburn 1 says that this plant-louse is attacked by a " red ; Of the ladybird beetles which attack this aphis, Fitch mentions Hippodamia parenthesis Say, Goccinella 9-notata Herbst, and Goccinella 5-notata Kirby, although it seems probable that Fitch was dealing with a different plant-louse, and he may not have observed them feeding on the oat aphis. At different times assistants of the Cereal and Forage-Crop Insect Invest
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 14 BULLETIN 112, U. S. DEPARTMENT OP AGRICULTURE. avence at La Fayette, Ind., and Washburn 1 says that this plant-louse is attacked by a " red ; Of the ladybird beetles which attack this aphis, Fitch mentions Hippodamia parenthesis Say, Goccinella 9-notata Herbst, and Goccinella 5-notata Kirby, although it seems probable that Fitch was dealing with a different plant-louse, and he may not have observed them feeding on the oat aphis. At different times assistants of the Cereal and Forage-Crop Insect Investigations have observed the following ladybird beetles, or their larvae, feeding on the oat aphis in various parts of the United States: Cycloneda munda Say, Goccinella 9-notata Herbst, Megilla maculata Scymnus sp., and Hippodamia convergent Guer. (fig. 9), the last species being by far the most abundant, and consequently the most useful of the coccinellicls in the control of the aphis. In addition to the foregoing enemies, the larva? of several species of lace-wing flies (Chrysopida?) are known to feed upon this aphis. Miss Margaret Morse, of Worcester, Mass., (in litt.) has found that quails eat these aphides in confinement, and while definite field observa- tions are lacking, it is quite probable that the quail, or bobwhite, as well as other birds fre- quenting grain fields, plays an important part in the control of this and other grain aphides. Among other natural agencies which assist in holding the aphis in check are fungous diseases. These, like most fungi-attacking insects, thrive best under moist conditions; hence the diseases commonly attacking plant-lice are most preva- lent and useful in moist seasons. Eains likewise have a beneficial effect, particularly " driving " rains. Webster,2 in his Ohio report, " suspects " two minute insects, Gonatocerus brunneus Ashm. [MS.] and Polynema longipes Ashm. (Gosmocena citripes Ashm.) as destroying eggs
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