I planted several geraniums because I was told they were easy to grow and pest-free. Well, that’s a bunch of bunk. My geraniums have green worms on them. They go right to the buds and feast on them. In addition, they’re destroying the future flowers by tunneling into the buds. What should I do?
Geraniums are a perfect choice for new and experienced gardeners.
They provide lots of color all summer and are primarily trouble-free; however, they are susceptible to a worm or caterpillar called Geranium Budworm or just Budworm. They’re not a problem every year and, unfortunately, your gardening experience has been spoiled. Besides geraniums, you will find Budworms on Petunias, Pelargoniums, and Flowering Tobacco plants.
The worm is the larva stage of a moth. The adult budworm moth lays eggs on the leaves and flowers of a geranium generally in the late evening. Upon hatching, the larvae or worms tunnel through the plant, damaging the flower(s). Most of their activity takes place at dusk and stops at sunrise.
The worms are small, around a quarter of an inch, but can grow to be half an inch or more before pupating. The pupa stage is the hibernation stage they go into before turning into a moth. It takes about a month for them to mature, and there can be two to three infestations per season. Because of their small size and ability to “match” the color of their host plant, Budworms can be hard to find or see without looking closely.
The early warning signs are the plants stop flowering or the flowers are riddled with holes. In addition, you may notice small holes in the stems and or black droppings. The color of the larvae can differ from brown to green with yellow stripes. The coloration is determined by the type of plant the larvae are feeding on, but usually, they are green.
Budworms are not that difficult to control as there are several organic solutions to the problem. During the day, budworms cluster around the base of the plant for shelter. However, they emerge to feast on the plant during the early evening hours, making this the best time to remove them manually.
Organic sprays include Spinosad and Baccillus Thuringiensis. Spinosad is found in Captain Jack Dead Bug Brew or similar products. It will give you immediate control. Bacillus Thuringiensis also known as BT, is often recommended, but it takes several days of feeding before the fatal stomach flu kills the worms. So in the future, you need to be diligent in checking your plants when watering for any signs of a new infestation. If found, you then apply a repeat application of your control.
This is an excellent time to prune and shape the plants. I would then follow up with feeding to force the lateral growth, making your plants fuller. Your geraniums should be back in bloom in mid-August to early September.