558 THE farmers' handbook. 



carted on to the patches and burned. The patches should be mown and 

 treated before the general crop is cut, as otherwise the parasite may be dis- 

 tributed throughout the field by the machinery. Burning is the safest 

 remedy, and will not injure the lucerne plants. 



Insect Pests. 



Tortrix glaphyriana, Meyrick (Lucerne Web Moth). 



The little leaf-rolling caterpillar of this moth is a well-known pest among 

 the lucerne fields in the Maitland district, and is more or less in evidence 

 nearly every season, but it is only now and then that it increases in such 

 numbers as to become a very serious pest. As a general rule, it appears 

 early in September, and does not disappear until the end of February. 



The caterpillar is a bright green grub, slightly over half an inch in length 

 and slender in form, with a white hair or bristle on the sides of each seg- 

 ment. Generally several live upon each head of lucerne in a mass of silken 

 threads and curled leaves, finally pupating in loose cocoons among the foli- 

 age. The small moth, which measures slightly over half an inch across the 

 outspread wings, is dull yellow, mottled with dark brown on the fore wings. 

 When a crop is found to be badly infested by this moth the farmer usually 

 cuts it down close and keeps it well fed off with stock. 



Bruchophagus funebris, Howard (Lucerne Seed Wasp). 



This .is a microscopic black chalcid wasp that punctures the young seed 

 and deposits her eggs beneath the skin, under shelter of which the little 

 maggot feeds upon the contents and pupates in the empty shell. When 

 matured it emerges from the pupal covering and gnaws its way out through 

 the side of the seed. Such a large percentage of lucerne seed is often so 

 damaged that the parcel is worthless. 



The only method of dealing with this seed-destroyer is to cut the crop 

 before the seed has ripened, and utilise it as a green fodder or convert it 

 into hay. 



Fungus Diseases. 



Rust. — A disease of the lucerne leaf due to the fungus Uromyces 

 striatus, Schroet. The leaf becomes dotted with small brownish spots, which. 

 if closely examined, are seen to be raised above the general surface of the 

 leaf. Some may have burst open, exposing a red-brown mass of rust spores. 

 The spots are usually better defined than those produced by the leaf-spotting 

 fungus {Pseudopeziza) . The discoloration is practically limited to the rust 

 pustule, whereas in the other case the margin of the spot is frequently ill- 

 defined, though the mid-region of the " spot " is much darker in colour, and 

 becomes raised to form a pustule, in which the spores are produced. 



Leaf Spot. — The fungus Pseudopeziza medicaginis, which causes " leaf- 

 spotting," is very different from the rusts in its characteristics. The leaf 

 shows its presence by numerous small brown discolorations on both sides. 

 The green colour is soon lost, and the bleached leaf readily falls to the 

 ground, whence the spores become scattered to attack fresh host plants. 



The usual method for combating both Leaf Spot and Eust is frequent 

 cutting of the crop, as the affected portions of the plants, or the greater 

 part, are removed each time before the fungi produce their full crops of 

 spores. 



