274 



JOURNAL OF AGRICULTURE OF I'. R. 



NEMATODES. 



A great many of the vegetable crops are attacked to a greater or 

 less extent by a minute thread-like worm, Heierodera radicicola, 

 which bores into the roots, causing them to swell, and stunting or 

 stopping the growth of the plant. Fig. 28 shows tlie work of this 

 worm or nematode on the roots of celery. 



Control. — Ground that is known to be infested with these worms 

 should be planted only to crops that are resistant or immune to their 

 attacks. Seedlings should be grown in sterilized seed-beds. Infested 

 land may be treated with applications of wood ashes, lime, or salt 

 to reduce the number of nematodes or with Cyanamid ^ at the rate of 

 from one to three tons per acre. 



SLUGS OR LAPAS."" 



These slimy, repulsive looking creatures 

 are very destructive to all green crops, and 

 occasionally do great damage to some vege- 

 tables. They are nocturnal in ha])it. hid- 

 ing during the day and coming out to feed 

 at night. It is usual during a season of 

 heavy rains for them to occur in destructive 

 numbers. 



Control. — The lapas may be cleared from 

 a field by collecting them at night with the 

 aid of lanterns. They may also be con- 

 trolled by placing fresh-cut leaves Vetween 

 the rows of plants in the evening, and 

 collecting in the morning the lapas that 

 have crawled under them. A light applica- 

 tion of lime on the soil around the plants 



Fig. 29.— Slug. 

 is also effective in protecting them from the lapas. 



WHITE GRUBS. 



There are several species of white grubs that do damage to our 

 truck crops. These grubs are the immature forms of the large 

 brown beetles known as "May beetles" or ''June bugs." They are 

 large, fleshy, wrinkled, white gi'ubs, that lie curled in a semi-circle 



^Watson, J. K., Florida Agric. Exp. Sta. Bui. 136. 

 ^ Veronicella occidentalis. 



