PPDL Picture of the Week for
November 7, 2011

Dodder on Muskmelon

Dan Egel, Vegetable Pathologist, SWPAC, Purdue University

Folks who regularly follow the “Picture of the Week” probably know that microorganisms such as fungi and bacteria can be parasitic on plants. The pictures accompanying this weeks article show a plant that is parasitic on another plant. The yellow plant covering the cantaloupe (AKA muskmelon) in figure 1 goes by the name of dodder. It is a plant that makes it’s living by sending a ‘probe’ into the host plant-in this case a cantaloupe plant-and extracting the fluid rich in sugars for the benefit of the dodder plant and the misfortune of the cantaloupe plant.

Dodder plants are yellow because they lack the green chlorophyll pigment that most plants use to make food from sunlight. Dodder plants don’t need the sunlight since they get their food from other plants. In figure 2, one can see that dodder plants do have flowers like many plants. In this picture, small insects are helping to pollinate the flowers.

Unfortunately, dodder plants can parasitize many types of plants, including ornamentals such as chrysanthemum (figure 3). However, melons such as shown here, alfalfa and clover are some of the preferred hosts for dodder. A crop rotation away from these plants may help to reduce the incidence of dodder the next year. It may be possible for home gardeners to collect the dodder and the affected plant and destroy both before the problem spreads too far. Finally, some preemergence herbicides may help reduce the spread of dodder

Click image to enlarge

Dodder on muskmelon

Figure 1

Close up of dodder

Figure 2

Dodder on chrysanthemum

Figure 3

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service