67 



Valley, Bay City, Port Lavaca, Austin, and Hamshire, and it prob- 

 ably occurs at Marlin. No doubt other localities which have not yet 

 come to our notice are infested. 



The females lay their eggs on the lower part of the stalk in cavi- 

 ties previously made while feeding. They also oviposit on the 

 tubers in the same manner, in shallow-planted potatoes or where 

 the tubers are easily accessible. The number of eggs that one weevil 

 is capable of laying could not be ascertained the past season, but in 

 the insectary the number was very small, which accounted for the 

 slow increase of the pest. Tlie first mating at College Station was 

 May 2. On May 6 mating pairs were common, but the first eggs 

 were found May 20. Tlie average time to the hatching of these eggs 

 Avas twelve days. The life cycle from mating to adult is forty-nine 

 days, allowing fourteen days from time of mating to egg-laying, 

 twelve days for eggs to hatch, sixteen days for larva? to develop, and 

 seven days for the pupse. The time from emergence to mating varies 

 from a few minutes to several davs. Experiments made in breeding 

 the insects on potatoes that had not yet the tul)ers formed were suc- 

 cessful. The young larva^ first bored clown in the stem, then up- 

 ward, in most cases the pupte being found several inches above the 

 groinid in the center of the stalk. On j\Iay 20 the first eggs were 

 found in the insectary. On December 7 of the preceding year speci- 

 mens of tubers sent in from Port Lavaca had all larvae half groAvn. 

 As the season of actiA^ty is longer at Port LaA^aca than at College 

 Station, four to fiA^e generations Avould haA^e ample time to develop. 

 Fumigation in the bin Avith car1)on bisulphid has been thus far the 

 main reliance. At College Station the adults fed voraciously on all 

 parts of the groAving plants, giA'ing the plant an appearance some- 

 thing like that given to the tomato Iw the flea-beetle. These adults 

 Avere all killed with Paris green and arsenate of lead sprays, the 

 latter insecticide requiring a longer time than the former. Tubers 

 in Avhich all stages of the insect Avei'e present in a healtlw condition 

 Avere receiA^ed at College Station at different times of the year. In- 

 fested sAveet potatoes can be shipped long distances,, and this is an 

 easy Avay of disseminating the pest. The old practice of allowing 

 the Amines and small tubers to remain in the field is unfortunately 

 still in vogue in many localities. Some growers folloAv the advice 

 given and destroy the remains of the crops after harvesting. They 

 feed the small tubers to cattle, holding that hogs refuse to eat them. 



Although the adult insects liaA^e wings, their chief mode of migra- 

 tion is on foot. This accounts for the relief obtained by planting 

 carefull}'^ selected seed remote from the infested territor^^ It is 

 important that good seed be thoroughl}^ covered Avith earth Avhen 



