MICE 229 



vation before the riee is sown. But this may result in making 

 the date of planting too late for best jdelds of rice. 



Another method of fighting weeds consists in applying no water 

 for a year or more, meantime not using the land for rice or even 

 for any crop. In this way, the dry-land weeds crowd out the 

 water-loving weeds, which latter are the most serious enemies of 

 the Louisiana rice grower. 



Insect enemies. — Rice is not greatly injured by many insects. 

 Among insect pests is the larva or grub of a small gray beetle, 

 the water weevil (Ldssorhoptrus simplex). The grubs in summer 

 feed on the roots of the plants, giving to the clumps of plants 

 affected a yellowish appearance. The remedy consists in pre- 

 venting the stagnation of the water and, if practicable, in the 

 temporary withdrawal of the water and the drying out of the land. 



Fungous diseases. — Rice blast, also called " rotten neck," is 

 thought to be caused by a fungus ( Piricularia oryzoe) . The sheath 

 node is attacked, that is the node in which the head is forming, and 

 the head may fail to fill out or may break ofi. Experts are not 

 agreed as to any practicable treatment for this disease. 



Rice rust causes the leaves to die and the grain to be Ught. The 

 cause is not definitely known. This trouble has been prevented 

 by using 400 pounds of kainit per acre. 



Rice smut ( Tilletia horrida) occasionally occurs, filling the kernel 

 with a mass of black spores. According to Anderson, it can be 

 prevented either by (1) scalding the seed for 10 minutes in water 

 kept at a temperature of 133° F., or (2) by moistening the seed 

 for about 2 hours in a solution of one ounce of formalin to 3 

 gallons of water. 



Rice birds or bobolinks (Dolichonyx oryzivorus). — These birds 

 prey on the ripening grain. Men and boys armed with shot 

 guns are employed in some localities to frighten these birds from 

 the rice fields. 



LABORATORY EXERCISE 



If seed heads or rough (unhuUed) rice can be obtained, write a 

 description of the seed and its covering, and of the arrangement 

 of seeds on the branches. 



