17 



the best results are obtained when the gas is allowed to act 

 for twenty-four to forty-eight hours at a temperature above 

 75 degrees. Do not fumigate when the temperature is below 

 60 degrees. This treatment will in no way injure the beans 

 for use as food or seed. 



Caution. — The gas is not dangerously poisonous to man, 

 but avoid breathing it as far as possible. Carbon bisulphid 

 is highly explosive, and therefore allow no fire of any kind in 

 the vicinity of this gas. 



7. Pea weevil, Mylabris (Bruchus) pisorum L. 



This species is a little larger than the bean weevil, but many 

 of their habits are similar. They differ materially, however, 

 in the number of annual generations, for the pea weevil has 

 only one, while the other may have several. Furthermore, 

 only one larva of the pea weevil invades a single pea, and 

 unlike the bean weevil this insect does not breed in dried 

 seed. 



Control. — Thoroughly fumigate all peas, before they are 

 stored in the fall, as directed for the control of the bean weevil 

 (see above), 



8. Bean aphis, AjMs rumicis L. 



This minute, blackish plant louse often causes considerable 

 injury to beans. 



Control. — Use nicotine sulphate as recommended on page 6. 



9. Pea aphis, Macrosiphum pisi Kalt. 



The pea aphis is one of the larger species of plant lice. It 

 migrates from its winter host, clover, to the young pea vines 

 early in the season, where it clusters about the growing tips 

 causing much injury. 



Control. — Spray thoroughly with nicotine sulphate as recom- 

 mended on page 6. 



Attacking Beets and Spinach. 



1. Cutworms (see page 9). 



2. Wireworms (see page 10). 



3. Flea beetles (see page 12). 



4. Blister beetles (see page 12). 



5. Plant Hce (see page 11). 



6. Plant bugs (see page 13). 



