14 MONTANA EXrERIMENT STATION BULLETIN 269 



Conservative estimates obtained from several different sources 

 show that the folUiwing acreages were partially or completely 

 (Icsti'oycd : 



Alfalfa 73,825 acres 



Gardens 5,685 acres 



Sweet clover 7,520 acres 



Field peas 525 acres 



Corn - 140 acres 



Total 87,695 acres 



The foregoing estimates do not include sugar beets. Being 

 1 tetter prepared to fight leaf -feeding insects, through cooperation 

 with the sugar companies who supplied arsenic and sprayers, the 

 l)eet growers were able to handle the webworm problem without such 

 extensive losses as occurred in the case of other field crops. 



The damage to gardens was very severe. As a result of the 

 drought the previous year many sections of the state depended on 

 gardens as the first local s:ource from which to replenish food sup- 

 plies. Sudden attacks by tremendous armies of webworms com- 

 pletely wiped out hundreds of such gardens and as many more were 

 badly damaged before any protective measures could be applied. 

 In some cases the webworms came in such great numbers that crops 

 were lost in spite of any and all combative practices. In one 

 instance an onion grower with excellent croj) prospects lost seven 

 uut of nine acres of onions within two days in spite of having sprayed 

 tlie plants with one application of Paris green. Not enough poison 

 could be put on the plants to save them. Wliere the web-worms 

 occurred in moderate numbers good success was obtained in gardens 

 through the use of heavy applications of Paris green or arsenate 

 of lead. 



lli-avy losses were incurred \>\ ttu' alt'alfa-seiHl growers. A large 

 pari ol" the alfalfa acreage \\'hicli would otherwise have I)een kept 

 for seed was cut early for hay. Young alfalfa suffered heavily as 

 much of this coidd uol withstand the att;u*k like older plantings. 



The over-winterini;' generation of moths (responsiI»le for the fii'st 

 genei-alioii of webworms), was very large in 1931 as well a.s in 1932. 

 In each of these years the flight of moths was so heavy fi-om i\Iay to 

 late June that there is sti-ong evidence that they were responsil)le 



