The Bulletin. 



23 



ROOT KNOT OF VARIOUS CROPS. 



Distribution in North Carolina. — This trouble occurs in sandy types 

 of soil in the eastern half of the State. 



Field Crops Affected. — Alfafa, vetch, soy bean, clovers, cowpeas (ex- 

 cept Iron), cotton, tobacco, potato, sweet potato, watermelon, cucumber, 

 cantaloupe, and tomato. Many other crop plants are affected as well. 

 A few of the common weeds that are susceptible are May-pop, wild 

 potato, pigweed, purslane, morning glory, and wild carrot. 



Fig. 11. Nematode Root-knot. A badly affected root-system, showing 

 the irregular swellings of various sizes. 



Symptoms. — Enlargements of irregular shape and size appear any- 

 where on the root system. These swellings involve the whole thickness 

 of the root, and are not merely outgrowths from the side as are the 

 bacterial nodules of leguminous crops. Affected plants are stunted in 

 growth and their foliage is a lighter shade of green than normal; this, 

 however, may be hard to detect when a large area is uniformly infected. 

 Badly affected plants may wilt when water is scant, or sometimes in the 

 hot sun when there is an abundance of moisture in the soil. 



