News from Hidden Valley Hibiscus

Symptoms		Cause
	White spots or patches on leaves →	Sunburn
	Brown edges on leaves →	Fertilizer Burn
	Buds start to grow, then discolor and fall off before blooming →	Thrips
	Buds turn bright yellow while still tiny and fall off before blooming →	Hibiscus Gall Midge
	Scratch marks on flower petals →	Thrips
	Leaves stipple, turn yellow, & fall off →	Spider Mites
	Tiny webs on stems & tips →	Spider Mites
	Leaves turn yellow and fall off until plant is defoliated, soil is neither too wet nor too dry →	Spider Mites
	White cottony mess on leaves →	Whiteflies
	Tiny bright white insects fly out of hibiscus when leaves are shaken →	Whiteflies
	Black, white, yellow, brown, or green insects on buds, flowers or leaves →	Aphids
	Black, white, yellow, brown, or green insects on buds, flowers or leaves →	Aphids
	Small, white cottony spots on leaves, and tiny white bugs fly out when plant is shaken →	Whiteflies
	Small, white cottony spots on leaves, and nothing flies out when plant is shaken →	Mealybugs
	Tiny, bright white spots on bark →	Snow Scale
	Tiny, black flying gnats around plant →	Fungus Gnats
	One wilted branch on an otherwise healthy plant →	Dieback Disease
	Plant defoliating from tip, moving down stem while rest of plant is healthy →	Dieback Disease
	Entire plant suddenly wilts soil is very dry →	Underwatering
	Entire plant suddenly wilts soil is wet →	Wilt Disease
	Black spots on leaves →	Leaf Fungus
	Holes in leaves →	Slugs or Snails
	Leaves eaten between veins →	Grasshoppers
	Leaves eaten away →	Rabbits
	Occasional yellow leaf on a healthy plant →	No Problem ~ Normal Leaf Shedding

Hibiscus Gall Midge

All I get is Tiny Yellow Buds and No Flowers! Why?

Microbud Infested with Gall Midge Yellow, Skinny, Drooping

Tiny yellow buds and no flowers is the classic symptom of the nasty pest, hibiscus gall midge. This midge, Contarinia maculipennis, is a small fly that lays its eggs in hibiscus buds, damaging the buds and making them fall off before they can develop and bloom. The effect for hibiscus gardeners is hibiscus that stop blooming - a very upsetting situation.

Hibiscus gall midge is not all over the United States yet. It is thought to be native to southeast Asia, and has been in Hawaii since the early 1900's where it is called "blossom midge." It was carried in plants to Florida in the mid-1990's, and since then has slowly moved along the Gulf Coast area, through Louisiana and into southeast Texas. If you live outside these areas, you will most likely be safe from hibiscus gall midge. But if you have bought plants from the Gulf Coast states, you could have imported this frustrating pest without realizing it.

Hibiscus gall midge are very similar to thrips. Like thrips, adult insects fly onto the bud to lay their eggs. The eggs hatch, and the larvae (little yellow worms) eat their way through the buds, destroying them as they munch, until they drop with the fallen bud into the soil beneath the plant. The larvae then burrow into the soil to pupate for about 3 weeks. When they emerge from the soil as adult insects, they fly away, then go find a new bud to lay their eggs in.

How Can I Tell if I have Hibiscus Gall Midge?

The first sign that your hibiscus have thrips and gall midge both is that the buds drop off before the flower opens. To tell the difference between these two pests, look at the fallen buds closely. Thrips allow the buds to get fairly big before they infest them. When thrips damage a bud, the petals are already visibly forming ("showing color") but the bud turns a rotten, grayish-brown color, then it falls off or stays on the bush and fails to open into a flower. Thrips larvae are so tiny that when you break open a bud, you can barely see them. If you do see them, they look like tiny black lines, like this typed hyphen: -

A Healthy Microbud ~ Plump, Green, Upright

Hibiscus gall midge, on the other hand, prefer to invade "microbuds" - the tiny baby buds that don't yet show any "color" or actual flower petals. Hibiscus midge turn these baby buds a bright yellow color, and completely stunt the growth, so the bud stays very small and falls off while still small. Many people have reported seeing the midge larvae inside a bud by breaking open the bud. They are visible yellow worms that are quite active. They can contract their bodies and "hop" about visibly.

How do I get Rid of Hibiscus Gall Midge?

Treating hibiscus gall midge takes some work. These resilient bugs can be quite hard to get rid of. It's important to carefully treat each stage of the midge's lifecycle.