Kona Coffee Plant

Asked June 25, 2016, 1:57 PM EDT

I have a Kona coffee plant that looks like something is eating the leaves. I've washed the leaves with soapy water and it they say to use a pesticide but don't say which one, could you recommend one to use? I did clean some brown spots off the stem and leaves. Also, some of the leaves had a sticky substance on them. Using the soapy water did remove the visual ones. Should I change the soil? Thank you.

Dakota County Minnesota insect issues plant health leaf damage coffee plant

1 Response

Thank you for the question. It sounds like there are two problems with your plant. The sticky substance and brown spots you were able to wipe off are probably caused by a scale type insect. Scales are usually found on plant stems and the undersides of leaves especially along mid-veins. They use needle-like mouthparts to feed on plant sap, secreting sticky honeydew as an end product of that process. They can be manged by frequent scouting and physical removal like you are doing, or you can use a pesticide, many of which are listed in our publication on houseplant insect control: http://www.extension.umn.edu/garden/insects/find/houseplant-insect-control/

The damage to the leaves will take more work to identify. If the plant is a recent purchase, it's possible that some sort of chewing larvae or slug came with it and have done damage. If you've had it awhile and recently started to move the plant outdoors to take advantage of the summer weather, a chewing insect could have done the damage. It's a little hard to tell from the photos but maybe tender new leaves were damaged by strong winds or rain. Examine the entire plant for a hidden creature and if found, simply pluck off and discard outside.

Thank you for contacting Extension.