INJURIOUS TO MELONS, CUCUMBERS, SQUASH, ETC. 387 



ive in bright, warm weather, when they reproduce most rapidly, 

 but in cool, moist weather they reproduce but slowly, and if such 

 a summer follows similar weather conditions during the spring, the 

 aphides multiply rapidly without a corresponding increase of their 

 enemies and serious damage results. Inasmuch as these same 

 enemies attack the cabbage-aphis, Professor C. E. Sanborn * has 

 suggested that the cabbage-aphis might be encouraged to multiply 

 on crops planted near melons or cucumbers, so that an abundance 

 of parasites and insect enemies might be in readiness to attack the 

 melon-aphis when it appears. This might be done by planting 

 kale, rape, or wild mustard in the fall, upon which the cabbage- 

 aphides will pass the winter and will multiply in early spring. 

 This trap-crop should be planted in rows around the prospective 

 melon-field, and if the latter be large, rows should be planted 

 through it. If the kale does not soon become infested with the 

 cabbage-aphis, transport some from the nearest cabbage-patch. 

 The ladybirds and parasites multiply rapidly with plenty of the 

 cabbage-aphides for food, and as soon as the food supply becomes 

 scarce they are forced to migrate and will search out any colonies 

 of melon-aphides. 



Control. The most important factor in the control of this, 

 as well as many other aphides, is constant watchfulness, inspect- 

 ing the plants frequently and destroying badly infested individual 

 plants and treating small areas before the pest becomes spread 

 throughout the crop. 



Where a few young plants are affected or before the leaves have 

 become badly curled, the aphides may be destroyed by spraying 

 with kerosene emulsion, containing 5 to 8 per cent kerosene, 

 whale-oil soap, 1 pound to 5 gallons of water, or tobacco extracts. 

 Emulsion must be carefully made or burning will result. The 

 aphides must be hit to destroy them, and it is necessary to use an 

 underspray nozzle (page 75), or to turn the vines over and then 

 re-turn them, so that all the aphides may be covered. After 

 the foliage is well curled it is practically impossible to reach the 

 aphides by spraying, and fumigation must be used. 

 * See Bulletin 89, Texas Agr. Exp. Sta., p. 44. 



