I did your course back in 1996, it seems to have changed a bit since then.
I'm now living in New Plymouth and I am wondering if anyone there knows any
organic controls for the green vegetable bug and the passion vine leaf
hopper. The vege bug loves beans, especially butter beans, although I find
it on other veges. I squash all I find, but its not enough as they damage
about half the crop.
The leaf hopper also loves beans, but is also on everything else, ornamental
or food plants.
Green Vegetable Bug, Nezara virudula, Hemiptera
It has two-three generations per year.
- Egg stage is about 20 days long and eggs are usually found on the underside of leaves.
- The nymph stage is about 80 days long. The young nymphs are orange with dark markings that develop to shining black nymphs.
- The adult stage is about 100 days and they are green, 10-13 mm in diameter. Mating takes place in spring and summer. Adults over winter in sunny positions on evergreen trees and shrubs such as citrus.
What do the bugs prefer? What happens if you disturb them?
They prefer sunny positions on host plants such as potatoes, tomatoes, black nightshade, tamarillos, beans, corn and passionfruit. Tomatoes and tamarillos get hard, corky growths where the bugs have pierced the fruits.
When the bugs are disturbed they can exude a brownish foul-smelling fluid, which will stain fingers or clothes and leave persistent odour. Because of this, most predators avoid the bug.
What do they do? What happens with the plants?
Both nymphs and adults suck the plant sap so plants wilt and shrivel and get stunted.
What to do to get rid of the pest!
- Green vegetable bug parasite: Trissolcus basalis, Hymenptora a wasp egg parasite that requires warm dry conditions, well established in the northern North Island.
- Vespid wasps: Common and German wasp: feed on both adult and nymph bug. Vespid wasps considered pests as well.
- Crop rotation to break the pests lifecycle
- Remove debris and weed growth to reduce over wintering sites.
- Row covers for the seedlings
- Hand-picking the bugs and squeeze them
- Spray with Neem oil. It acts as a deterrent and anti feeder. Biodegrades within two weeks when exposed to sunlight. Repeated application.
- Spray with pyrethrum. Poisonous to all insects. Repeated application necessary since it does not kill the eggs. Do it in the evening when bees and beneficial insects are not active. Less burning of plants as well. It breaks down in 48 hours.
- Row covers for seedlings
- Hand pick them
- Companion plants such as geranium and petunia, marjorams, coriander, chamomile, yarrow.
What happens with the pest when you use Neem spray and/orPyrethrum spray?
- sometimes the spray will interfere with the metabolism of the insect and it will die.
- Neem spray acts as an anti feeding agent
- Pyrethrum is lethal to all insects and should be used with care! Preferably use in evenings
For more information - Penny Woodward’s Pest-Repellent Plants (ISBN: 1864470283). Also try Flyingpig.co.nz for this book, and to search for the following:
Judy McMaugh: What Garden Pest or Disease is That?
R.R. Scott, Editor: New Zealand Pest and Beneficial Insects
On the web: HortNet: Gives information about everything concerning horticulture.
Passion Vine Hopper, Scolypopa australis. Hemiptera.
The Passion Vine Hopper populations grows at the rate of one generation a year. They overwinter as an egg, with this stage lasting about six months. The eggs are inserted in plant stems, with relatively soft, dead or dying stems seem to be preferred. The nymph stage lasts about three months. They are greenish with a fluffy tail - visible around October. The adult stage lasts about 3-5 months - look for light brown small moths 8-10 mm around December.
What do the hoppers prefer? What happens if one disturbs them?
- temperate parts of North Island and Nelson area in the South Island.
- Host plants are flax, bracken, Fuchsia, Lantaria, Coprosma, berry fruits, beans, privet, kiwifruit, tutu, citrus, hydrangea, tecomaria, jasmine.
- If disturbed they lift and a cloud of them will be seen.
What do they do? What is the damage?
They suck sap from succulent shoots and the result is distortion of fruit and leaves. Plants will get stunted, wilted and dieback overall. Because of the copious production of honeydew the likelihood of sooty mould is very high.
They also play a role in the production of poisonous honey. They feed on tutu’s sap ~ a sap released from the plant and then collected by honeybees which is highly poisonous to humans.
What can you do about the pest?
- Heavy winter pruning of egg laying sites.
- Crop rotation to break the pest’s life cycle.
- Spray them with Neem. It acts as a deterrent and anti feeder. Biodegrades within two weeks when exposed to sunlight. Repeated application.
- Spray with Pyrethrum. Repeated application necessary since it does not kill the eggs. Poisonous to all insects. Pyrethrum is poisonous to all insects so do it in the evening when bees and beneficial insects are not active. Less burning of plants as well. It breaks down in 48 hours.
- Time of sowing, when pest is less.
- Row covers for seedlings
- Hand pick them
- Companion plants such as geranium and petunia, marjorams, coriander, chamomile and yarrow.
For more information:
Penny Woodward, Pest-Repellent Plants
Natural Control of Garden Pests, French, J.