Understanding their impact on n fruit and how to manage them naturally
The Mango Flower Beetle (Protaetia fusca and related species) is a well-known visitor to Rare Dragon Fruit and other farms and gardens in our area.
Although often seen in mango trees—where their name comes from—they are far from selective.
These chunky, copper-coloured beetles are attracted to nectar, pollen,fruit, and anything sweet, making them a common sight around dragon fruit farms.
But are they pollinator friends, or a serious pest? The answer is: both.
Why They Are Considered a Pest
1. Damage to Flowers
Adult beetles feed on pollen, nectar, and soft flower tissue.
In large numbers they can:
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shred petals
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damage flower structures
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reduce effective pollination
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reduce fruit set
While they can incidentally help with pollination, the damage they inflict often outweighs the benefit—especially for growers who rely on healthy flowers for fruit production.
Root Damage from Larvae
Larvae are the classic white “C-shaped curl grubs” found in soil. They feed on:
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plant roots
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organic matter
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decaying fruit
In large numbers they can weaken or kill young plants, particularly in shallow, dry, or compacted soil. While we usually only find one or two, high populations can be destructive.
4. Serious Damage to Dragon Fruit
On our farm, Mango Flower Beetles cause one of the most frustrating forms of dragon fruit damage.
They typically:
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choose one or 2 fruit fruit per post, only 2 in 150 posts will be affected
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chew into the soft skin
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create wounds that lead to rot
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attract other beetles
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turn that fruit into a mating ground
It’s not uncommon to find 10–20 beetles gathered inside a single damaged fruit. Once a fruit is breached, it cannot be saved.
Identification
Mango Flower Beetles are:
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Coppery brown with pale patterns
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Chunky, oval-shaped like typical scarabs
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About 15 mm long
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Often grouped with “flower beetles”
They are active most of the year, but populations explode in the warmer months when flowers are open and fruit is ripening.
They thrive in:
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Australia
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Southeast Asia
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The Philippines
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Fiji
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India
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Hawaii
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Recently parts of North America
Reproduction & Life Cycle
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Females lay eggs 2–13 cm deep in moist but not waterlogged soil.
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Eggs are white and oval and hatch within 2–4 weeks.
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Larvae take about 7 weeks to develop before pupating and emerging as adults.
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Grassland, lawn areas, and undisturbed soil are preferred breeding sites.
Understanding this cycle helps identify when to interrupt it.
How to Control Mango Flower Beetles Naturally
Because these beetles visit flowers, spraying chemicals is not an option—it would harm bees, pollinators, and your plants.
Here are safe and effective methods:
1. Maintain Plant Health
Strong plants can withstand minor damage. Good soil, moisture, and mulching help prevent stress, making fruit and flowers less vulnerable.
2. Good Garden Hygiene
One of the simplest and most effective strategies:
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Remove rotting fruit
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Clean up dropped dragon fruit
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Don’t leave split or damaged fruit on the plant
Rotting fruit invites beetles and becomes a breeding and feeding hub.
3. Encourage Predators
Many natural predators will eat beetle larvae, including:
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Magpies, ibis, and other birds
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Parasitic wasps
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Robber fly larvae
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Tachinid flies
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Predatory beetles
Healthy biodiversity helps keep populations stable.
4. Disturb the Soil During Larval Season
Lightly roughing up the soil in warmer months can:
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expose eggs and larvae
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dry out breeding sites
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make larvae available to predators
Avoid deep digging around dragon fruit roots, but light disturbance is beneficial in surrounding areas.
5. Fungal Control (Naturally Occurring)
A naturally occurring entomopathogenic fungus can infect and kill larvae.
This isn’t something you apply—rather, maintaining moist, organic-rich soil encourages a healthy soil biome where these fungi thrive.
6. Weather, Competition, and Natural Cycles
Population declines often occur naturally due to:
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heavy rain
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high heat
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predation
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parasitic insects
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soil disease affecting larvae
Observing seasonal shifts helps anticipate problem months.
How We Manage Mango Flower Beetles at Rare Dragon Fruit
At our farm, we focus on natural, chemical-free methods that protect pollinators, preserve soil life, and maintain a healthy ecosystem.
1. Encouraging Natural Predators
One of our most effective strategies is simply supporting the wildlife that already helps us manage pests.
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Ducks patrol the orchard and happily eat the beetle larvae (curl grubs) living in the soil. They naturally forage, and reduce larval numbers before they mature into adults.
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Native insectivore birds such as magpies, butcher birds, and native ducks also help keep populations down by feeding on larvae and occasionally adults.
By encouraging these predators, we maintain a balanced ecosystem where pests are kept in check without disrupting beneficial insects like bees.
2. Removing Infected Flowers & Fruit
When beetles chew into a dragon fruit, they often turn it into a meeting ground. It’s common to find 10–20 beetles crowded inside a single damaged fruit.
When we see this happening, we:
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Place a plastic bag over the damaged flower or fruit
This traps all beetles inside without allowing them to fly off and infest other plants. -
Carefully remove the fruit (with the beetles enclosed)
This prevents escape and stops further feeding and mating. -
Freeze the bagged fruit
Freezing humanely puts the beetles “to sleep” and prevents future breeding cycles.
3. Companion Planting
Companion planting with Queen Anne’s Lace provides an alternative food source for mango flower beetles, helping divert their attention and giving your dragon fruit flowers a break.
This method is clean, safe for the environment, and avoids spraying anything harmful on flowers or around pollinators.
Rare Dragon Fruit do not use pesticides or herbicides on our farm, and this natural approach helps us effectively manage small outbreaks of beetles.
