336 Kansas State Board of Agriculture. 



Prevent pigweeds from going to seed, and avoid sowing the seed in 

 grain, grass and clover seeds. Frequent and thorough cultivation of the 

 seed bed before sowing the crop will destroy a large part of the seeds 

 of this weed which are in the surface soil. 



DODDER (Ciiscuta, species). Dodder is a parasite deriving its food, not 

 from the soil, but directly from the crop plants which it infests. In this 

 respect it is not like the ordinary weeds of the farm. It starts from a 

 seed, at first deriving its nourishment from the food supply stored in the 

 seed. It develops a slender, threadlike and leafless stem, which twines 

 around the clover alfalfa or other suitable host plant with which it 

 comes in contact. Suckers are sent out which penetrate the tissues of the 

 host plant. From this time on the dodder is dependent on its host for its 

 food supply, and by means of the suckers penetrating the sap-conveying 

 tissues, begins to drain the host plant of the food prepared by the latter 

 for its own use. After becoming established on the host plant the part 

 of the dodder below the point of attachment dies. Above this point the 

 plant makes rapid growth, branching out until under favorable conditions 

 it forms a tangled mass of threadlike filaments. Since dodder does not 

 manufacture its own food, but uses that prepared by the host plant, it is 

 devoid of leaves and root. 



Dodder plants are to be distinguished by their slender, threadlike 

 stems, which are lemon yellow, orange or pink in color. They may ap- 

 pear to confine their attack to a single plant in a place, or may spread 

 uniformly from plant to plant, either near the ground or from the tops 

 of the plants. Small white flowers, mostly in clusters, are produced by 

 midsummer. Seeds ripen throughout the central United States from 

 the middle of July into September. As a rule the dodders are profuse 

 seed producers, but seed production is strongly influenced by the char- 

 acter of the host, its treatment as a crop, and by climatic conditions. 



Dodder is commonly thought to be just one species or kind of plant, 

 but there are several different kinds of dodder that are very common 

 and others that are not so common. Alfalfa and clovers alone are in- 

 fested by four common species, viz., field dodder, clover dodder, small- 

 seeded alfalfa dodder, and large-seeded alfalfa dodder. Dodder is pe- 

 culiar in that the different species show a marked preference for cer- 

 tain kinds of host plants. 



The seed of dodder becomes an important impurity of commercial 

 seeds, both on account of the injurious nature of the plants and the 

 fact that they occur in nearly all the regions in which clover and alfalfa 

 seeds are produced. The size and weight of the dodder seeds and the 

 period of their maturity agree so closely with those of red clover and 

 alfalfa seeds that their presence in the seed crop is practically sure to 

 follow the occurrence of maturing dodder plants in fields devoted to 

 these crops. 



Success in the eradication of this pest depends very largely on the 

 early discovery of the plants, followed by immediate work in subduing 

 them. It is important to gain control before the plants have spread far 

 from the point of attack, and to destroy them before they produce seed. 

 Cutting the infested area close to the ground, and burning the plants on 



