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How to identify it
- Adults are about 0.03 inch (0.7 mm) long, orange-yellow, with thin brown bands between the segments of the abdomen and three small red dots (simple eyes) on top of the head. The wings are fringed.[1]
- At rest, the wing tips reach past the end of the abdomen.[1]
- First-stage larvae are white to pale yellow; second-stage larvae are larger, sturdier and bright yellow. Larvae line up along the main veins on the undersides of young leaves or sit anywhere on young fruit.[1]
- A closely similar species, Neohydatothrips burungae, has been found on avocado; it is often darker brownish, has bands only on the upper side of the abdomen, and may need an expert to tell apart.[1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Citrus thrips | Very similar, but its light orange-yellow to whitish body has no bands across the abdomen.[1] |
| Western flower thrips | Occurs on avocado without damaging it, mostly in flowers. It has thick bristles at the tip of the abdomen, and at rest its abdomen extends past the wing tips.[1] |
| Predatory thrips | Larvae of beneficial predatory thrips can look like avocado thrips larvae, but predatory thrips are seldom seen in large numbers.[1] |
Where it lives
An invasive pest of avocado groves in California; a 2002 study described it as a new avocado pest in the state.[2][3]
Biology and life cycle
Females hide their eggs inside the undersides of leaves, in young fruit and in fruit stems. Development runs through two feeding larval stages and two non-feeding pupal stages.[1]
About three-fourths of the larvae drop from the tree to pupate in the top layer of dry, undecomposed leaf litter; the rest pupate in cracks on the tree. Pupae are rarely seen.[1]
It does well in cool weather. Numbers build on young leaves in late winter and spring and peak in late spring and early summer; warm, dry weather later in the season holds them down.[1]
There are six or more generations a year, and egg to adult takes about 20 to 30 days at average temperatures of 65° to 75°F.[1]
In laboratory work, survival from larva to adult was best at 20°C (68°F), females laid the most eggs (about 40 each) at 15°C, and adults lived about 52 days at 15°C but only about 2 days at 30°C. Unmated females produce only sons.[2]
Damage and signs
- Feeding on very young fruit leaves scabby or leathery brown scars that spread across the skin as the fruit enlarges, sometimes called alligator skin. Severe early scarring can slow or stunt fruit growth. Wind rub can cause similar scars.[1]
- Almost all fruit damage happens when the fruit is 0.2 to 0.6 inch long. Hass fruit can be fed on until it is about 2 inches, but scars rarely form on fruit larger than about 0.75 inch.[1]
- Thrips move from leaves to fruit when the spring flush hardens off. On young leaves they cause irregular bronzing along the midrib and veins, which usually matters only if very high numbers cause leaves to drop early.[1]
- Avocado thrips has little effect on tree health, and the inside of the fruit is not affected, but scarred fruit is severely downgraded or culled.[1]
Health risk
UC IPM treats it purely as a fruit-scarring pest of avocado and describes no risk to people.[1]
Control
Prevention
Pruning and fertilizing practices change how much tender foliage the tree carries during fruit set. Extra leaf flush during fruit set keeps more thrips on the leaves and off the fruit, and pruning in January, which does not lower yield compared with pruning in February to April, may encourage that flush.[1]
Sanitation
A coarse organic mulch about 6 inches deep under the trees may reduce survival of thrips that drop to pupate. Its effect on thrips is uncertain, but mulch also helps control Phytophthora root rot and weeds.[1]
Traps and physical control
Start checking newly flushed leaves in February and March, then every 7 to 10 days from April: inspect the undersides of 10 young leaves on at least 10 trees with a hand lens. An average of three to five thrips per leaf at fruit set is the general guideline for treatment.[1]
Biological control
Predatory thrips are its most important natural enemies, especially Franklinothrips orizabensis, which multiplies quickly in mild weather when avocado thrips is increasing. Banded-wing thrips, black hunter thrips, green lacewings and at least one parasitoid also attack it. Natural enemies do not always hold numbers below damaging levels.[1]
Pesticides
UC IPM lists spinosad (an organically acceptable formulation is available) and spinetoram, with no more than one application of either a year, and abamectin no more than once every three years, to slow resistance. Choose selective materials so natural enemies of other avocado pests survive.[1]
In California field trials, imidacloprid applied through the irrigation system was taken up so slowly that levels in new leaves stayed too low to control avocado thrips.[4]
Common questions
- What causes brown, leathery 'alligator skin' on avocados?
- Avocado thrips is a common cause in California. Larvae feed on fruit when it is under about 0.6 inch long, and the scars spread as the fruit grows. Wind rub can leave similar marks.[1]
- Are scarred avocados still good to eat?
- UC IPM says avocado thrips does not affect the internal quality of the fruit; the damage is to the skin, which lowers its market grade.[1]
- When do avocado thrips do their damage?
- Mostly in late spring and early summer, when numbers peak and the leaves of the spring flush harden, pushing thrips onto newly set fruit.[1]
Sources
- University of California Statewide IPM Program, “Avocado Thrips, UC IPM Pest Management Guidelines: Avocado.” ipm.ucanr.edu/agriculture/avocado/avocado-thrips (accessed 2026-11-09)
- Bulletin of Entomological Research (Cambridge University Press), “Developmental and reproductive biology of Scirtothrips perseae (Thysanoptera: Thripidae): a new avocado pest in California (Hoddle 2002, Bulletin of Entomological Research 92:279-285), abstract.” pubmed.ncbi.nlm.nih.gov/12191435/ (accessed 2026-11-09)
- Journal of Economic Entomology (Entomological Society of America), “Investigating alternatives to traditional insecticides: effectiveness of entomopathogenic fungi and Bacillus thuringiensis against citrus thrips and avocado thrips (Zahn and Morse 2013, Journal of Economic Entomology 106:64-72), abstract.” pubmed.ncbi.nlm.nih.gov/23448016/ (accessed 2026-11-09)
- Pest Management Science (Society of Chemical Industry), “Field evaluation of systemic imidacloprid for the management of avocado thrips and avocado lace bug in California avocado groves (Byrne et al. 2010, Pest Management Science 66:1129-1136), abstract.” pubmed.ncbi.nlm.nih.gov/20623704/ (accessed 2026-11-09)
- iNaturalist, “Scirtothrips perseae taxon page (order and family).” www.inaturalist.org/taxa/701683 (accessed 2026-11-09)