Ruud Kleinpaste
Ruud Kleinpaste proposes a novel way to deal with passionvine hoppers.
How to beat passionvine hoppers.
passionvine hoppers were numerous in our old garden in Auckland, but here in Christchurch, it’s a different game: nada, nothing, zilch, zero! I don’t miss them at all.
I have the feeling that their nuisance line ends somewhere in Marlborough, with some “good” years and some “bad” years from time to time.
All I remember was a regular assault starting around October and finishing well into late autumn. They were everywhere, and had a go at anything with a photosynthetic pulse and a phloem bundle.
Somewhere on the Gardener’s Twitbook-feed there’s a statement that says: “It’s probably easier to list the plants these hoppers do not use as a host!”
I also remember that Aucklanders often called them lacy-winged moths – it shows you that entomological knowledge has always been rather slow to sink in up there in the North Island.
They are certainly not moths – these critters belong to a totally different insect order: the Homoptera, or sap-sucking bugs. Yes these are insects you can legitimately call “bugs” in entomological parlance.
Their big deal is a pretty nifty and long tubular sucking snout which they use to feed with. If you hold a passionvine hopper and look at its underside, you can see that sucking tube nicely tucked between its legs.
A hand lens or jewellers loupe might come in handy, though!
As with most other true bugs (including aphids, mealybugs, green vegetable bugs, scale, whitefly and psyllids), the aim is to mainline on the phloem juices that transport the sugars produced in the green leaves – a process called photosynthesis.
They’re after the sweet stuff that carries the nitrogen which is useful for the manufacture of protein. That nitrogen is the key element to create bodies, eggs and offspring!
The sweet by-product is simply evacuated in the form of honeydew and splattered all over the leaves and stems below; sticky, sweet honeydew that attracts ants, wasps and bees. It’s also a great substrate for a famous black fungus that covers the host plant in a serious infestation: sooty mould.
If we add all this up, it appears as if this originally Ozzie sapsucker robs the plant of carbohydrate building blocks, while pooing all over the leaves, blocking sunlight, impeding photosynthesis and causing a mass feeding frenzy for other invasive insects, such as wasps and ants.
Plants often suffer as a result and the vast quantity of these hopping and flying bugs in a garden can also cause distress to most gardeners during the warmer months of the year – they often end up up your nostrils!
Controlling these insects is not easy at all.
When you arrive with an insecticidal spray, the bugs simply jump aside and escape the lethal droplets; they’re quick! The only time this works is when the tiny nymphs (minute fluffy bums) have just hatched in October.
Just envelop them in a cloud of simple fly spray on a wind-still morning. Jump as they might try, they’ll get more and more active ingredient on their tiny bodies – it’s fatal at that stage. The next opportunity for some preventative control comes in autumn (May onwards), when all the females have laid their eggs in thin twigs and tendrils, ready for overwintering. The oviposition sites are unmistakable: little fluffed-up insertions at very regularly spaced intervals. During the autumn pruning session, the usual thing to do is cut off the egg sites and burn them. That will remove a good part of next year’s generation of passionvine hoppers. However, someone drew my attention to the fact that these passionvine hoppers often have minute wasp parasites inside these eggs – and you wouldn’t want to kill these biological control agents! So, how about trying to give these tiny Hymenopterans a chance to do some great work. Collect as many of the passionvine hopper oviposition sites as you can and store them in a perfectly sealed icecream container with some slightly damp paper towels, to stop them from dehydrating during winter. In October, let the fluffy bum nymphs hatch and die inside the container. Then wait till the tiny wasplets emerge in early summer and set those free. Let’s try this trick, North Islanders, and don’t forget to report your findings to NZ Gardener.
The next opportunity for some preventative control comes in autumn, when all the females have laid their eggs.