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Pest and disease management

What pests and diseases affect dragon fruit?

Common pests

Dragon fruit can be affected by several pests:

1. Thrips: Cause scarring on fruit, deformation, and leave fecal deposits that turn reddish-brown to black.
2. Mealybugs: Feed by sucking sap from tender parts of plants and are often protected by ants.
3. Scale insects: Small insects that suck sap and can weaken the plant.
4. Leaf Hoppers: Cause stippling (tiny pale dots) on stems and can spread disease.
5. Ants: Often farm and protect sap-sucking pests like mealybugs.

Common diseases

Major diseases affecting dragon fruit include:

1. Stem and Root Canker: Caused by Neoscytalidium Dimidiatum, appears as dark, yellow small spots with red spots mixed in.
2. Anthracnose: Fungal disease (Colletotrichum Gloeosporioides) causing halo-like concentric lesions on stems and fruit.
3. Stem Rot: Can cause yellowing and rotting of affected branches.
4. Botryosphaeria Dothidea: Causes blotchy red/brown spots on stems, sometimes with a bull's eye appearance.

Organic control methods

For organic pest and disease management:

1. Natural predators: Introduce beneficial insects like ladybugs and lacewing larvae to control pests.
2. Organic sprays: Use chili or garlic spray (1 cup chillies, 1 clove garlic blended and soaked in water for 24 hours, mixed with Castile soap).
3. Cultural practices: Proper spacing, good air circulation, and avoiding overhead irrigation can reduce disease pressure.
4. Weed management: Regular weeding and using weed mats can reduce pest habitats.
5. Companion planting: Growing pest-repelling plants like marigolds and basil nearby can help control pests.

Telling fungal from bacterial

If you find a pathogen of some sort on your branches, scratch it and smell it. If it smells musty and grassy, it's likely a fungus. If it smells rotten, then it's likely a bacterial infection. You want to use different treatments for each situation.

Fungal: Use a copper fungicide spray on rust and similar fungal infections. Symptoms normally clear after a few applications and this treatment can be found as OMRI certified products (organic use).

Bacterial: These tend to be more serious infections requiring you to cut away any and all infected material down to the cambium. Cutting away all discolored material until there is nothing but green flesh (no yellow). Now spray the stem and remaining flesh with full strength hydrogen peroxide (spray bottle is best). This will disinfect the flesh and bleach the stem. This should be done in the evening to prevent sun scald.

If neither method proves effective you should remove the branch to avoid the infection spreading further. Beware if you have multiple plants in close proximity as an infection can spread quickly from one plant to the next. The best way to fight infection is to stay ahead of it with early detection.