Do you have Fruit Spotting Bug in your fruit trees? Without doubt it is the worst pest we have here in Bundaberg, and if I didn't take control measures, I would have no fruit at all from some of my trees. Actually there are two varieties, Ambypelta nitida and Ambypelta lutescens lutescens, the latter supposedly being the most prevalent in this region. Admittedly I haven't taken the time to note the difference since they are both equally a pest anyway.

Mostly the bug attacks the small fruit, in some cases causing it to drop off soon after, eg. mangoes, persimmons, white sapote, Lychees, custard apples, macadamias, etc. On other fruit trees, the fruit is damaged almost beyond use, eg. guavas, natal plum, stone fruit. It also attacks the unopened flowers on custard apples and persimmons, causing them to die.

The new pink mango tips, juicy new custard apple shoots and mulberry tips are sensational food and the shoot is soon misshapen and badly scarred - some small ones wilt and die. Pawpaw tops are not immune either and the young leaves don't develop after being attacked. The nymphs of the bug though very tiny can be just as destructive as the adult.

The only known predators are certain spiders, assassin bugs and egg parasitoids found in North Queensland. No pheromone attractant has yet been discovered. The only registered spray to use is Endosulfan.

We have fruit spotting bug on our house block as well as on our tree block 0.6 km away, but Bill Rehbein growing fruit commercially 1.5 km further on has no problem with them.

You never know which tree you'll find them on. For days you can check a tree and find none and then - they're there again. I've been checking morning and late afternoon when I am able. They don't seem to be around much if the tree is in the wind or if it is wet or in the heat of the day.

They are very shy creatures and will attempt to hide if they spot you. If really worried, the adult will fly off or drop to the ground and disappear quickly. I find a hand under the fruit or branch and one over the top usually causes the spotter to drop into the underneath hand. The nymphs will run, and if small, can easily be lost. They also drop if all else fails.

The eggs are usually laid singly in the tree in which the young and adult will live, but the adults fly from one tree to another. The egg is 1.7 mm long, pale green and slightly opalescent.

Eggs hatch in 6 - 7 days. After a day, the nymph is red with black spots on back and antenna. We caught some fruit spotting bugs and put them in a bottle with some young mango tips. After a while, they mated and laid. Nymphs hatched after 6 days and gradually grew in size. They seem to moult a number of times as they grow bigger. A generation is complete in 34 - 38 days. An adult mates within 5 days of maturing and repeated matings are needed for egg fertility. Only a few eggs are laid each day, but they can lay up to 163 eggs in a summer. There are 3 or 4 generations in a year.

Being a native to Queensland, the fruit spotting bug originally had certain native host trees, eg. umbrella trees, white cedars, corky passionfruit, rough leafed fig, eucalypts, but now they have adapted to feed on almost everything I grow, even tips of hibiscus and frangipani plants.

Endosulfan is the spray recommended, but I haven't found it really effective and its effects only last for a while - of course if I misted the whole area as they do on fruit farms, maybe the results would be better, but what would the neighbours say?

One year during 21 searches in November, I killed 47 nymphs and 46 adults, and in 17 searches up till the 18th December, I killed 53 nymphs and 47 adults.

I have many questions to which I can't get answers. Some of these are:

Doesn't the bug attack fruit close to the ground? I find on some trees that I have fruit only near the ground but none elsewhere, so I leave the lower branches on some trees.

Where are the eggs laid in the wild? I have yet to locate eggs on any of my trees.

Is there any other means of control besides spray? Sometimes I use bags to protect the fruit but putting them on is time-consuming.

By manually catching the bugs, am I likely to reduce their numbers appreciably?

Why are certain varieties of mango more susceptible to the bugs than others?

Why are the bugs prevalent in certain areas while there are none in others?

Would the bugs be responsible for spreading die-back in pawpaws?

How can a creature as small as a fruit spotting nymph do so much damage to fruit and young shoots?

Considering the damage done by this pest, why hasn't more been found about it? It's certainly something that needs a lot of research!

If you have answers to any of these questions or other information about this pest, I would like to hear from you.

Bill Tunstall, (N.E.C. Member)

DATE: August 2000

* * * * * * * * * * * * * * *