One of the common pests that attack sunflowers are helicoverpa worms. There are two main species of helicoverpa that are known to infest sunflowers – the native budworm (Helicoverpa punctigera) and the corn earworm (Helicoverpa armigera). These pests typically occur from the late budding stage of the sunflower plant until late seed fill.
I have encountered these helicoverpa pests in my own sunflower garden, and they can cause significant damage if not managed properly. The worms feed on the developing flower buds and can also bore into the developing seeds, leading to yield losses.
One way to identify if helicoverpa worms are attacking your sunflowers is by observing the damage they cause. The worms chew holes in the flower buds, causing them to wither and die. You may also notice frass, which is the excrement of the worms, around the damaged buds.
To control helicoverpa infestations, there are several strategies that can be employed. One option is to use biological control methods, such as releasing beneficial insects that prey on the helicoverpa worms. For example, certain species of parasitic wasps can lay their eggs inside the helicoverpa larvae, effectively killing them.
Another approach is to use insecticides specifically targeted towards helicoverpa worms. These insecticides can be applied directly to the sunflower plants, targeting the pests and reducing their populations. It is important to carefully follow the instructions on the insecticide label and ensure that it is safe to use on sunflowers.
Cultural practices can also be implemented to reduce helicoverpa infestations. For instance, planting sunflowers earlier in the season can help avoid peak helicoverpa populations. Additionally, maintaining good garden hygiene by removing any debris or weeds that may serve as alternate hosts for the pests can help minimize their numbers.
If you notice holes in the flower buds of your sunflowers and withering of the buds, it is likely that helicoverpa worms are attacking your plants. It is important to take action to control these pests to prevent further damage and yield losses. Implementing biological control methods, using targeted insecticides, and practicing good garden hygiene can all contribute to managing helicoverpa infestations in sunflowers.