432 ANNUAL EEPORTS OF DEPAHTMENT OF AGRICULTURE. 



Based on reports received from orchardists, it is estimated that 

 not less than $100,000 worth of trees were saved in the Yakima 

 Valley as a result of these poisoning operations and that the com- 

 bined savings for all counties would amount to not less than $250,000. 

 One grower stated that he had " 55 trees damaged before poisoning ; 

 none after poisoning; all damage stopped; value to me, $500." 

 Another grower writes : " Poisoned as near 100 per cent as possible ; 

 believe every tree in my orchard (4,800) would have been killed." 

 These statements are typical of many received from other orchard- 

 ists. Trees once girdled have relatively little chance of complete re- 

 covery. Bridge grafting maj^ save a good percentage, but the fruit 

 is usually lost for a period of two years and the trees weakened to 

 such an extent that often they blow over. The injured parts also 

 afford harborage for insect pests, particularly the woolly aphis. 



In Idaho, field mice were not very numerous during the past year 

 and did damage in only a few communities. Poisoning operations 

 were conducted in Ada County, where 480 acres of orchard were 

 treated, 600 quarts of poisoned bait being used. 



Pine mice continued to do much injury in orchards when the ground 

 was covered with snow, and considerable loss of potatoes, sweet 

 potatoes, and other root or tuber crops and flower bulbs was reported. 

 The experiments conducted resulted in developing a much more effec- 

 tive poison preparation and in devising a simple and relatively inex- 

 jjensive method of distribution. Very satisfactory protection was 

 thus given to orchards, as the poison so distributed continues effective 

 for a long period during the winter. 



Pocket mice did a considerable amount of damage to grain in parts 

 of Adams and Franklin Counties, Wash. A few farmers applied 

 control measures, but relatively little work for the destruction of 

 these rodents was undertaken, despite the fact that pocket mice can 

 be controlled very easily. 



In the control of kangaroo rats, which at times cause extensive 

 damage to open ranges, a limited amount of assistance has been given 

 landowners. In many instances, where infestation is heavy, kangaroo 

 rats are a critical factor in determining the numbers of livestock 

 that can be grazed on the area and interfere materially with natural 

 reseeding by destroying quantities of seeds of native grasses. They 

 also, attack fields of sprouting grain and various vegetable crops. 

 As a result of demonstrations given in El Paso County, Tex., several 

 hundred pounds of oatmeal baits were distributed to protect the 

 cantaloupes on irrigated lands. An expenditure of $30 in this in- 

 stance saved several thousands of dollars worth of melons to the 

 producers. 



WOODCHUCKS. 



Many complaints of unusual abundance of woodchucks and dam- 

 age by them have been received during the year from points through- 

 out the northern United States. These animals not only damage 

 garden vegetables, but also alfalfa, clover, and other valuable forage 

 plants. Their burrows often cause erosion to start, resulting in the 

 washing out of extensive gullies. Investigational work was con- 

 ducted in the Eastern States with a view to determining baits and 



