Dr. Dave Shetlar, Ohio State University Extension entomologist, noted last week that he is seeing fairly high populations of grasshopper nymphs (newly hatched) in the central Ohio area.
What this means to me is that I need to check my ornamental grasses and any other grass-like plants and possibly spray a pesticide if populations are high. If I let them go to the adult stage, I may not have any ornamental grasses left to enjoy this fall!
Dave suspects that our populations are good this year because of the drought last year. Grasshopper eggs have a better survival rate when soils are dry. If the soils are wet, the eggs won’t survive. I am sick of the wet weather and wet soils but maybe there is a positive in it after all?
I have seen great fluctuations in grasshopper populations over the last several years. One year the populations were so high in our Gateway Learning Gardens that you couldn’t walk through the garden without one jumping on you. Last year, we have very few grasshoppers.
The fluctuation is due to weather conditions as mentioned above and is one of the reasons why grasshoppers are really bad in the semiarid parts of the US.
Grasshoppers are general feeders and really like ornamental grasses, lilies, and corn. Their feeding on the edge of the leaf blade results in a really ragged looking plant.
I don’t normally spray pesticides to kill grasshoppers but if populations are high, I will.
Another pest that is causing damage at this time is the sunflower head-clipping weevil. This insect basically clips the flower stems of sunflowers as well as coneflowers which results in the flower heads flopping.
The weevil doesn’t take off the entire stem but rather creates a hole to lay her eggs in the stem. The flower head just flops over but still remains attached to the stem, making it pretty easy to identify the culprit.
This insect doesn’t seem to be widely distributed in Ohio but Joe Boggs, Extension Educator in Hamilton County has reported it in this part of the state. In fact, there is a particular field of coneflowers in the Yellow Springs area that has had them every year for the past several years.
There are no pesticides labeled to control this weevil. The best method to control it is hand removal of the broken flower heads. This prevents the weevil larvae from completing development.
Do this gently and you can remove the adults, as well. Drop the flower heads with adults into a bucket of soapy water.