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🐛 Pests & Diseases
Aloe's toughest enemies are not insects but conditions: standing water and plant stress. Healthy plants in draining soil shrug off most attacks — your first line of defence is agronomy, not chemistry.
The IPM mindset
- Prevent: clean planting material, perfect drainage, wide spacing for airflow, no leaf wounds.
- Scout: walk the field weekly; look at leaf bases, crowns and new growth.
- Act early and surgically: remove affected leaves/plants the day you see them.
- Spray last: if needed, use neem-based or recommended products per local guidance, respecting buyer residue limits — aloe feeds food and cosmetics industries, and residues are a rejection reason.
Quick pest identification
Aloe Gall Mite
Warty galls, grotesque distortion. Most feared. Uproot & burn immediately. No chemical cure.
Mealybugs
White cottony clusters at leaf bases. Sticky honeydew. Drench with neem oil.
Scale Insects
Brown hard bumps on leaves. Prune infested leaves, neem spray.
Spider Mites
Fine stippling, webbing in hot dry weather. Keep irrigation steady.
Termites
Hollowed bases, soil tunnels. Remove mound soil, treat at planting.
Nematodes
Stunted patches, poor roots. Rotate with marigold before replanting.
Disease severity & response time
Insect & mite pests
| Pest | Symptoms | Management |
|---|---|---|
| Aloe gall mite (Eriophyes aloae) — “aloe cancer” | Gnarled, wart-like galls and grotesque distortion on leaves, crowns and flower spikes; tissue looks cancerous | The most feared aloe pest. Uproot and burn affected plants immediately; never ship or compost galls. Source mite-free planting stock; avoid carrying infected sap on tools. Monitor nearby ornamental aloes as reservoirs. |
| Mealybugs | White cottony clusters at leaf bases and roots; sticky honeydew; ants traffic | Clean suckers before planting; drench crown with neem oil or recommended insecticide; remove heavily infested plants; control ants. |
| Scale insects | Brown/dark hard bumps on leaves; yellowing around them | Prune and destroy heavily infested leaves; neem or horticultural oil sprays; encourage natural enemies. |
| Aphids | Clusters on young leaves/flower stalks; sticky leaves | Usually self-limiting outdoors; strong water jet, neem spray; protect ladybird beetles. |
| Spider mites | Fine stippling, dusty look, webbing in hot dry weather | Water stress invites them — keep irrigation steady; miticide or neem if spreading. |
| Termites | Hollowed bases, soil tunnels up leaves; sudden plant collapse in sandy soils | Remove termite-mound soil from the field; apply recommended soil treatment at planting in known hotspots; avoid burying woody debris. |
| Nematodes | Stunted patches, poor root systems, decline over seasons | Soil testing; rotate with marigold or non-host crops before planting; use compost and clean stock. |
| Rodents | Gnawed leaf bases near hedgerows | Field-edge sanitation and standard control measures. |
Diseases
| Disease | Cause | Symptoms | Management |
|---|---|---|---|
| Root & collar rot | Water moulds (Phytophthora, Pythium), Fusarium | Outer leaves yellow, soften and collapse; base brown and rotten; foul smell; plants lift out easily | Number-one killer. Prevention: drainage, raised beds, no overwatering. Remove and destroy infected plants with surrounding soil; drench neighbourhood plants with recommended fungicide; replant gaps only after soil dries. |
| Bacterial soft rot | Erwinia spp. | Wet, slimy, foul-smelling collapse, often after injury or waterlogging | Same prevention as root rot; avoid leaf wounds; sanitize tools between plants; rogue out infected crowns. |
| Leaf spot | Fungi (Alternaria, Cercospora) | Small brown-black spots with yellow halos that enlarge and merge; mostly in wet, humid spells | Improve airflow; avoid overhead irrigation; remove spotted leaves; copper-based or recommended fungicide in severe outbreaks. |
| Aloe rust | Rust fungi (e.g., Phakopsora) | Orange-brown powdery pustules, mostly on older leaves | Cosmetic mostly; remove worst leaves; avoid dense wet canopies; fungicide only in commercial outbreaks. |
| Anthracnose | Colletotrichum spp. | Sunken dark lesions on leaves after rain/wounding | Drainage, airflow, wound avoidance; copper sprays on young outbreaks. |
| Stem/crown rot | Mixed fungi/bacteria | Crown of clumps rots, especially in old, overcrowded fields | Thin clumps (lift excess suckers); remove rotting debris; improve drainage. |
Physiological problems (not pests, not diseases)
- Sun scorch: bleached, reddish or white patches after sudden exposure of nursery stock or after pruning neighbours. Harden young plants gradually.
- Chilling/frost injury: water-soaked, glassy leaves that later dry black. Prune off dead tissue once weather warms; replant if the crown is dead.
- Edema (oedema): small corky bumps after overwatering in cool humid weather — fix irrigation, not chemistry.
- Tip dieback from salt/fertiliser burn: leaf tips dry after heavy fertiliser or salty water. Flush soil with light irrigation, re-test.
Prevention checklist
- ✅ Drainage designed before planting — beds/ridges above water level
- ✅ Clean, certified suckers from mite-free sources
- ✅ Drip or furrow irrigation, never sprinklers over leaves in humid weather
- ✅ Weekly scouting with a notebook — map where problems start
- ✅ Tools cleaned between fields (mites and rot travel on sap and soil)
- ✅ Removed leaves and galls burned or buried far from the field
- ✅ No standing water for more than a few hours, ever