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GRASSHOPPERS AND COFFEE TREATS

Giant grasshopper in coffee

Bruno Pinese, Harry Fay, & Rod Elder, Department of Primary Industries and Fisheries.

Coffee- Giant grasshopper (Valanga irregularis) nymphs. NB the two dark marks on the hind femura.
Giant grasshopper (Valanga irregularis ) nymphs.
NB the two dark marks on the hind femura

Description

Adult

The giant grasshopper is the largest of the short horned (antennae) grasshoppers in Australia, with adults growing up to 90 mm long. Adults are creamy brown to grey. Their colouration and markings are extremely variable, hence the species name (variabilis). Giant grasshoppers have enlarged hind legs used for jumping and short antennae. They have a spur or peg on the throat between the forelegs. Adults can be distinguished from the spur-throated locust (Austracris guttulosa) by their larger size, the absence of a white stripe along the top of the body, the blacked-tipped orange to red spines on the hind leg tibia (instead of black tipped white spines) and 2 dark marks on the top of the hind femura in both adults and nymphs.

Immature stages

Eggs are 5 to 6 mm in length and are laid in pods up to 90 mm deep in moist soil. The pods consist of up to 150 eggs at the bottom of the tubular hole with a frothy plug from the top of the eggs up to the soil surface. The frothy plug has a less dense area up the centre and, at hatching, hoppers escape by moving up this centre. Nymphs (hoppers) are pale green and wingless on hatching.. They later develop a black stripe down the middle of their back and the green colour may change to light brown as they approach the adult (winged) stage.

Life history

Eggs are deposited in October-November. There are seven nymphal stages before adulthood is reached.

Nymphs are present from September to March and adults from April to November. No breeding takes place during winter. There is one generation per year.

Distribution

This grasshopper is native to tropical and subtropical Australia and is found throughout Australia from about Sydney north.

Host range

The giant grasshopper feeds on a wide range of shrubs, trees and herbaceous plants including hibiscus, coffee and citrus.

Management

Importance

Minor and sporadic in coffee.

They are commonly found in home gardens, but are less common in commercial orchards. It is a pest of many garden plants in addition to citrus and coffee.

Damage

Coffee- Giant grasshopper adult

Giant grasshoppers feed mainly on foliage and sometimes on very young coffee berries. They are often very patchy with concentrations of nymphs close to where they emerged from the soil.

Deep feeding gouges on very young berries heal to disfiguring chalky-white scars.

Edges of leaves and tips of shoots are chewed.

Action level

When monitoring for other pests, check for damaged leaves, or for the presence of grasshopper adults and nymphs. Examine five plants at six locations widely spread throughout the crop.

Action is required when 25% or more of young shoots are damaged by giant grasshoppers.

Control methods

Cultural

In home gardens, grasshoppers can be removed from plants by hand and destroyed. They are most readily detected in the early morning when they tend to bask in the sun on the tops of foliage.

Biological

The small wasp Scelio flavicornis parasitises eggs. The adults and large nymphs are parasitised by flies from the genus Blaesoxipha. The adult flies are about the size of a house fly. Their larvae (maggots ) eat out the insides of their host and kill it as they leave to pupate through a hole in one of the inter segmental membranes often between the head and thorax.

Chemical

It might be possible to spot spray heavily infested areas. This will require fairly intensive monitoring throughout the crop.

Recommended chemicals

None

Note: This information was correct at the time of publication. However, it is the user’s responsibility to ensure that registered agricultural chemicals are used in accordance with legal requirements. (See Further information).

Always read the label.

October 7th, 2010
Topic: AGRICULTURE, FOOD DRINK, FRUIT VEG SMALL CROPS, Grasshoppers, INSECTS REPTILES, PESTS DISEASES BACTERIA VIRUSES Tags: , , , , , ,

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