428 Thirtieth Annual Ricport 



WORK ON POISON PLANTS 



The work on poison range plants begun last year has been con- 

 tinued. The commoner poison plants in the southern and central 

 parts of the State have been studied carefully, both in the field and 

 by means of numerous plant collections. Data have been collected 

 relative to their poisonous properties, their seasons of growth, flow- 

 ering, and fruiting, and conditions favoring or discouraging their 

 growth. Some work has also been done on practical means of 

 eradication. In the instance of loco plants, digging seems to be 

 the simplest method. The plants are invariably killed when cut 

 off at the roots two to four inches below the crown. Even wherfc 

 the plants are moderately abundant on grazing ranges, a consider- 

 able area can be cleared by one person in a week's time with a good 

 sharp hoe, or better, a spud. The latter is a tool resembling a hoe, 

 but with a short, straight neck and a stout blade about two-thirds 

 as wide as a common hoe. 



On the majority of grazing ranges in southern Arizona the 

 loco plants grow rather scatteringly and are rarely abundant. But 

 even where they are abundant on the range it is recommended that 

 they be dug out. It is only necessary to dig out the larger and 

 more luxuriant growing plants, since these are the ones from which 

 stock eat enough of the loco forage to produce the disease. The 

 smaller and weaker plants will either die out during the year or 

 else grow to be large enough the following year so as to be easily 

 seen. As far as possible, no loco plants should be allowed to 

 mature seed, and to prevent this the cutting or digging should begin 

 either before or by the time that the plants first begin to flower. 



Occasional reports of stock poisoning, apparently caused by 

 plants that are not known to be poisonous, have been received 

 from different localities. In some instances stockmen suspect very 

 strongly certain plants as causing the trouble. Some of the plants 

 that are believed to cause stock poisoning, at least at certain seasons 

 of the year, are rayless golden-rod or burro weed (Bigeloicia coronopi- 

 folia and B. Hartwegi), B. hctcrophylla, B. H'rightii, Baccharis ptcro- 

 Hoidcs, Lupinus Kingii, and a species of Ijnum. \\'(irk now is being 

 done on some of these plants. 



In the vicinity of Dewey, Arizona, during February and March, 

 1919, stock were poisoned on several different occasions from eating 

 bledo or careless weed (Amaranthus Palmeri) hay. This case of 

 poisoning was so apparent that it could not reasonably be doubted. 

 The hay was fed in racks in stock corrals, and the animals were 

 healthy and in good condition. Practically all the animals that ate 



