Mealybugs
White, waxy, cottony sap-suckers that mass on stems and fruit, drain the plant and shrug off sprays behind their wax coat.
- Pest type
- Waxy sap-sucker
- Attacks
- Stems, leaf axils, fruit
- Worst in
- Warm, dry weather
- Main risk
- Resists sprays; honeydew/mould
Overview
Mealybugs are soft, oval sap-suckers covered in a white, powdery or cottony wax that gives colonies the look of cotton wool packed into leaf axils, along stems and on fruit. They move slowly, so they build dense, sticky colonies in one place rather than spreading fast.
That wax coat is the whole problem: it repels water-based sprays, so mealybug is one of the hardest pests to wet and kill. They drain sap, deform growth and smother the plant in honeydew and black sooty mould, and in cotton and fruit crops (grapes, mango, guava, papaya) a heavy colony can render the produce unsaleable. Ants protect and spread them for the honeydew.
How to identify it
- White, cottony or powdery masses packed into leaf axils, along stems, under the calyx of fruit and on the underside of leaves.
- Under the wax, soft oval insects with fine waxy filaments around the body; colonies feel sticky.
- Sticky honeydew and black sooty mould on leaves and fruit below the colony, and ants patrolling the plant.
- Growth near the colony is stunted, twisted and yellowed.
The damage it does
- Sap drain that stunts and distorts shoots, wilts and yellows leaves, and weakens the whole plant.
- Honeydew and thick sooty mould that blacken leaves and fruit, cutting photosynthesis and market value.
- In grapes, mango, guava and papaya, colonies on the fruit make it unsaleable even at low pest numbers.
- Severe, spreading infestations in cotton that are very hard to knock down once established.
When to act
- Scout stem forks, leaf axils and fruit calyxes early — mealybug is far easier to stop as small starter colonies than after it spreads.
- Watch for ant activity, which both signals and spreads mealybug; a rising ant trail is an early warning.
- Because established colonies resist sprays, prevention and early action matter more here than for most pests.
Organic & cultural control
- Manage ants (sticky bands on trunks, destroying nests) — cutting off the ants exposes mealybugs to their natural enemies.
- Release/conserve the mealybug destroyer beetle (Cryptolaemus montrouzieri) and parasitoids, the mainstay of mealybug biocontrol in grapes and cotton.
- Spray neem oil, and add a wetting/spreading agent so the spray penetrates the wax; a fish-oil rosin soap improves coverage.
- Prune out and destroy heavily infested shoots and fruit, and remove alternate weed hosts around the field.
Chemical control
- The wax coat blocks sprays, so add a wetting agent, spray to run-off covering axils and undersides, and repeat to catch newly-hatched crawlers.
- CIB&RC-registered options include buprofezin 25% SC and thiamethoxam/other neonicotinoids where registered for the crop — choose accordingly and rotate groups.
- Time sprays to the crawler (young, un-waxed) stage, which is far easier to kill than adults; a second spray 10–14 days later catches the next hatch.
- Confirm the current recommendation and dose for your crop and zone with your local KVK.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
There are white cottony clumps on my plant stems and fruit. What are they?
Those are mealybug colonies — soft sap-suckers wrapped in white waxy, cottony threads. They cluster in leaf axils, along stems and on fruit, drain the plant and coat it in sticky honeydew and black sooty mould. They spread slowly but are hard to control once established.
Why do sprays not work well on mealybugs?
Their waxy, cottony coat repels water-based sprays, so the chemical never reaches the insect. Add a wetting/spreading agent, spray to run-off into the axils and undersides where they hide, target the young crawler stage, and repeat. Controlling the ants that protect them, plus the Cryptolaemus beetle, does much of the real work.
Why are there so many ants around my mealybugs?
Ants farm mealybugs for their sugary honeydew — they protect the colonies from predators and even carry mealybugs to new plants. Managing the ants (sticky trunk bands, destroying nests) is a key step: once the ants are gone, natural enemies like the mealybug destroyer beetle can bring the colony down.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.