90 Diseases of Truck Crops 



living green plants and are termed parasites, or from 

 dead organic matter and are referred to as sapro- 

 phj^es. Some higher flowering plants, too, have lost 

 the power of manufacturing their own food, and have 

 degenerated to the extent of assuming a parasitic 

 life. Of those which concern the trucker may be 

 mentioned the dodder. 



DODDER {CuSCUta sp.) 



Dodders or love vines are a group of flowering 

 plants which are closely related to the Convolvtdus 

 or Morning glory fanuly. Dodders are peculiar in 

 that they are destitute of the green coloring matter 

 chlorophyll, and for this reason must lead a parasitic 

 life. The plant obtains food by actually sending its 

 own roots into the tissue of the attacked green plant. 



The Parasite. When the dodder seed germinates 

 it is at first able to support itself and it then consists 

 mainly of a yellow, threadlike stem. This independ- 

 ent existence is maintained until the food in the seed 

 is used up. By this time the yoimg tendril-like plant 

 attaches itself to its host (fig. 17 a, b) and sends in 

 suckers or feeders which penetrate the interior tissue. 

 The attacked plant naturally becomes weakened and 

 may even die as a result of being robbed of its food, 

 which is taken up by the dodder. After reaching 

 maturity, the parasite blossoms and forms seed in the 

 usual way as any other flowering plant. 



Methods of Control. Dodder is often introduced as 

 seed mixed in with the seed which we buy. By care- 



