Garden Talk

with Rebecca Jordi


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Q: The buds of my hibiscus are turning yellow and dropping off. What is wrong?

Hibiscus bud midge maggot

Hibiscus bud midge maggot

A:  After opening one of the yellowing buds we discovered the hibiscus bud midge maggot, Contarinia maculipennis.  The female midge deposits eggs on the tips of the newly forming buds and within 24 hours the maggot develops and starts to feed on the bud.  It takes about one week for the insect to mature to the next stage; then they drop to the ground to pupate. The soil must be moist, which is generally not a problem in our landscapes.  It will take about 2 -3 weeks to mature into an adult. The adult midge is very small – similar to a mosquito. Although hibiscus is the favorite, the bud midge has been known to also infest tomatoes, jasmine, plumeria, other vegetables and ornamentals. There are other reasons for flower buds to turn yellow and drop off such as over watering, too much nitrogen, thrips or aphids, and very hot, dry weather.  However, since I found the maggot, I am going to blame it on the bud midge.  The best thing for homeowners to do is to be sure to clean up any buds and leaf litter which have dropped to the ground.  If the hibiscus plants are in the ground they may not need supplemental watering aside from what we get with rain.  Remember, the midge requires moist soil to pupate.  Contact chemical sprays don’t work well since they cannot penetrate the bud.

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