COMMON NAME

Mango flower beetle

Order

Suborder

Family

Genus

Species

Alias

Coleoptera

Scarabaeoidea

Protaetia

Protaetia fusca

Mottled flower scarab, Asian mango flower beetle

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Description

They have the typical scarab shape of a chunky, oval body. This beetle is a coppery -brown colour with lighter coloured markings. They are commonly grouped with other species of “flower beetle”. Their name is thought to have come about because of their presence on mango trees.

Adult size: 15mm

Out and about

These beetles will be about most of the year but numbers increase in the warmer months when plants are out in flower and fruit is ripening. They like the warmth of tropical and sub-tropical regions, particularly in most of Southeast Asia, Philippines, Fiji, India, Australia, Hawaii and recently North America.

Reproduction and Life cycle

The females lay eggs in the soil, preferring grassland. The soil must not be too wet or too dry. Eggs can be laid either singly or in clusters at a depth of 2 to 13 cm below the surface. Eggs are white and oval-shaped hatching in 2 to 4 weeks. It takes about 7 weeks for the larvae to reach adulthood.

To deter

To control

It is important to have healthy plants and good soil condition. When the soil is shallow and plant growth is restricted by dryness and, in the case of pastures overgrazing, the plants ability to recover from damage is reduced. The adult beetle is very tough and difficult to get rid of but encouraging predators will help. -Removal of rotting fruit is an important part of good housekeeping and will lessen the attraction of these beetles to the garden -There is a fungus that will kill the larvae -Roughing or lightly tilling the soil may help to destroy eggs and grubs (during the warmer months) and expose them to predators Populations are controlled by weather conditions, parasitism by insects, disease and predation by birds and insects. It is difficult to deter them from the flowers as anything sprayed there will affect bees.

Plants to repel

Plants to attract

Predators

Predators will attack the larvae of beetles Birds (particularly magpies and ibis)/ Parasitic wasps/ robber fly larvae/ tachinid flies/ predatory beetles. There is a naturally occurring fungus that will kill the larvae.

Why they are a Pest

The adult beetles feed on nectar, pollen and rotting fruit. Potentially the adults have the capacity to damage flowers in their efforts to get at the pollen and nectar, and therefore reduce fruit set. Their choice of flowers is not restricted to mangoes and certainly damaged flowers are not wanted in the case of ornamental plants. They can help with pollination. They can also be a pest of bee hives; attracted to the pollen (the bee stings do not bother them). The larvae, which are typical “c” curl grubs, live in the soil where they feed on plant roots. I could imagine that if they were present in large numbers that they may be a problem; but we did not find more than one or two, and they were more interested in the rotting fruit we had left around.

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