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I won’t tell – part II

April 18, 2017

3rd instar

Last month I wrote a post describing how, for a number of reasons, I had secretly released some newly hatched insects into my wife’s vegetable garden. Of course my cover was blown when she happened to read the post in question (who would have thought!). However I got into serious trouble when soon afterwards the little critters which had initially disappeared turned up in great numbers as instars of the vegetable pest, the Southern Green Shield Bug (Nezara viridula) and proceeded to damage our tomato crop.

4th instar

The term instar is used to describe the larval form of insects that moult several times before becoming an adult. The number of instar states differs with species. This shield bug has 5 instar states (some are pictured) each of which last about a week. The lifecycle from the egg to hatching the adult is between four to five weeks.

5th instar

Like all bugs the Southern Green Shield Bug has piercing-sucking mouthparts. They pierce the plant or fruit and pump digestive enzymes into it allowing the bug to suck out the liquefied food. The surface area of the fruit around the puncture mark becomes brownish or black in colour and very often sunken, causing a dimpled appearance – not good for the market value of the fruit.


As we are not selling the tomatoes I feel that there has been no harm done and we have progressed the field of science by identifying what insect the eggs were from.

That opinion is not shared in this household.

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