Ask the expert: Dodders can attach to stems of host plants and cause damage

Editor's note: Throughout the growing season, Mike Hogan, OSU Extension Educator for Agriculture & Natural Resources in Franklin County, will answer gardening questions submitted by Dispatch readers. Send your questions to hogan.1@osu.edu.

Q: A yellow vine-like plant that does not appear to have any leaves is covering my garden plants and is beginning to grow on some plants in my perennial bed.  It does not seem to be rooted in the ground and I have no idea where it is coming from.

A: The plant invading your garden is likely a dodder, a parasitic plant in the morning glory family (Convolvulaceae). There are 13 species of dodder found in Ohio, with the most frequent being common dodder, also known as swamp dodder (C.gronovii) and field dodder (C. Pentagona). We see common dodder the most in Ohio, many times covering garden plants such as pepper, eggplant, carrot and also on tall grasses and prairie plants in uncultivated fields. Many times dodders are found growing along waterways or in floodplains.

Dodders have thin tendril-like stems that attach to the stems of host plants. These plants lack adequate amounts of chlorophyll and are usually yellow or orange in color.  Dodders have modified root systems called haustoria which extend into the vascular system of host plants, allowing the parasite plant to extract water, carbohydrates and nutrients. Many times host plants are weakened by dodders making them more susceptible to plant diseases.

As soon as small stems of dodder are detected, they should be removed and discarded in household trash. Once dodder attaches to and winds around plant stems, it is difficult to remove these parasitic plants and damage to host plants might be inevitable.

Q: We had very little rainfall in August and September so my lawn turned brown. Now that some rainfall has returned, most of my lawn has greened up nicely, except for some large patches that remain brown. How can I tell  if these dead patches are due to grub damage or the dry weather?

A: One of the simplest methods for determining if grubs have killed turf is to try to pull the dead turf up by tugging on the dead crowns of the grass plants. If the dead sod is easily pulled away, almost like rolling up carpet, that is an indication that grubs destroyed the roots in that area. 

Adult grubs can also be found close to the surface at this time of year. If you find grubs, an application of Sevin will likely be the most effective approach as it will kill grubs that are still feeding and those that have ceased feeding. This insecticide must be watered into the soil with at least ¼ inch of water.

If grub damage is not the answer in these brown patches, it is likely that the grass plants have died due to a lack of moisture. In this case, now is the perfect time to re-seed these patches. Don’t wait until spring, as cool season grasses established in early fall tend to develop stronger root systems than those planted in spring and summer.