80 



EELWOEMS. 



especially in wheat, known as "purples," "ear-cockles," or 

 "peppercorns." 



We may often notice in several parts of an ear of wheat 

 that there are in place of the grains dark purplish - brown 

 galls, having a striking resemblance to a seed of the "corn- 

 cockle plant " (fig. 30, a). On cutting open one of these " galls " 

 the interior is seen to be full of a mass of a whitish-yellow colour, 

 which contains thousands of eelworm larvae, varying from .^i^th 

 to YTth of an inch long (fig. 30, c). When these galls are re- 

 sown with the wheat-seed, the apparently dried-up worms (e) 

 come to life, and the eelworm larvae enter the soil. On the 

 sound seeds germinating, the larvfe make their way to the nearest 



^ rootlets of the seedling plants, 

 and then bore between the 

 leaf-sheath and the haulm, or 

 in the terminal bud. As the 

 plant grows they ascend, and 

 quickly get into the ear and 

 swell out the ovary (the 

 future grain), whose walls 

 become first dark-green and 

 then purplish-brown. From 

 sixteen to twenty are found in 

 the lowest flower of the ear, ten to twelve in the next, and from 

 four to five in the topmost blossoms. As soon as they enter the 

 flower the worms become sexually mature, and then lay from six 

 hundred to sixteen hundred ova, which give rise to the larvae we 

 find in the ear-cockle later on in the year. 



. 30. — Ear-cockles in Corn (Tylenchus 



grain : c, larvte in cut grain d ; 

 larvie. (Greatly enlarged.) 



The Stem Eelworm {Tylcnclius dei-aMairix). 



This small eelworm especially attacks oats, where it produces 

 the disease spoken of as " Tulip Eoot." It also attacks wlieat, 

 oats, onions, hops, and many flowers, and is one of the causes 

 of " clover sickness." Beans and peas also sufi'er. It works 



