EFFECT OF SOIL APPLICATIONS OF INSECTICIDES ^ 



Fordhook Lima Beans 



In 1949 excellent stands and yields of Fordhook beans were 

 obtained in both treated and untreated plots. In 1950 wireworms 

 destroyed much of the seed in three of the untreated plots, and the 

 stands and yields were reduced accordingly. To determine wire- 

 worm abundance, a row of corn was planted in each plot on Feb- 

 ruary 21, and 7 days later two soil samples, 3 feet long and 4 inches 

 wide and deep, were taken in each of these rows and sifted. No 

 wireworms were recovered in any of the treated plots, whereas 

 larvae of the sugar-beet wireworm (Limonius calif ornicus Mann.), 

 1.2 per foot of row, were found in the untreated plots. 



Observations were made in 1950 on the extent of seed-corn 

 maggot injury to the bean cotyledons. The beans in the plots 

 treated with aldrin or chlordane were free of injury, but injury 

 was evident in the untreated plots and in those treated with 

 ethylene dibromide. Slight injury was also noted in the toxaphene 

 plots. The infestations of wireworms and maggots and the treat- 

 ments did not significantly affect the yields. 



In 1951 the differences in yields were within the limits of experi- 

 mental error, but there was a tendency for yields to be lower in 

 the plots treated with aldrin, chlordane, and toxaphene, as was 

 the case also with the Ventura beans in that year (table 2). 



Cabbage 



Cabbage plants were grown each year in flats and then trans- 

 planted in the plots at 2-foot spacings in rows 30 feet long. Plant- 

 ings of the Cannonball variety were made on April 18, 1949, and 

 of the Danish Ballhead variety on February 21, 1950, and March 

 7, 1951. Harvest began about the middle of June and terminated 

 during July. Yield data were obtained by weighing each market- 

 able head after the four wrapper leaves had been removed. 



In 1949 yields were low in all plots owing to the delayed plant- 

 ing. In 1950 and especially in 1951 yields were above average 

 for this crop, except in the toxaphene plots. No significant differ- 

 ences were noted in the size or appearance of the cabbage in plots 

 receiving different treatments, or between cabbage from treated 

 and untreated plots. (Table 2.) 



Cauliflower 



Cauliflower of the Medium Pearl variety was used in 1950 and 

 of the Early Snowball variety in 1949 and 1951. The plants were 

 grown in the greenhouse and transplanted in the plots at 2-foot 

 spacings on April 18 in 1949, on February 21 in 1950, and on 

 March 7 in 1951. There were 14 plants per plot each year. The 

 time of harvest varied, beginning the latter part of May in 1951 

 and the first week in July 1949. Usually three cuttings were made 

 over a period of 2 weeks. Yield data were obtained by weighing 

 the individual heads. To determine whether the size of the plant 

 had been affected, the leaves minus the roots were also weighed. 



