Limonicus lucky dip
Two months ago Tineke de Jong made a fascinating discovery in the greenhouse – a tiny white mite, fast-moving and nearly transparent.
She and husband Frans, owners of Southern Belle Orchard in Matamata, sent a sample to Zonda, the country’s leading specialists in biological pest control, to see what they had found.
‘‘From experience, we know that fast-running mites are hunters, looking for eggs or juveniles or whatever it is they’re after,’’ Mr de Jong said.
The results came back with a name for their mysterious mite – amblydromalus limonicus, a vigorous predator found throughout New Zealand.
‘‘It will prey on potato-tomato psyllids, thrips, whitefly and can also survive on pollen if it needs to.’’
Mr de Jong, whose business supplies supermarkets, restaurants and farmers’ markets, said the mite had made a huge difference to the number of pests in their 1500 sqm greenhouse.
‘‘Using natural predators to control pests is a big part of what we do. We use a mite for thrips and sticky traps and parasitic wasps for aphids.
‘‘That we got limonicus here is a lucky dip, it must have come in somehow.’’
Zonda entomologist Terril Marais said limonicus had massive potential as a form of biological control and could save the industry millions, except for one problem.
‘‘ They’re very hard to rear because they’re cannibalistic. That can happen when you’re trying to raise predators in a confined area.
‘‘The development of a financially viable rearing system is going to be the make-or-break of them.’’
She said that although little research had been carried out on the mite in New Zealand, Koppert Biological Systems in Holland had been working on it for 20 years and had just released it to the public as a form of biocontrol under the brand name Limonica.
‘‘They’ve obviously cracked it somehow, which is very exciting over there.
‘‘It would be nice if the industry could get behind it and fund a masters or PHD student or something. That’s definitely on our wishlist because it would be great for New Zealand’s industry.’’
New Zealand was something of a collecting ground for beneficial mites, Ms Marais said.
‘‘I know Canadian scientists came out at some stage to collect some predatory mites to reinvig- orate their colonies, and the food mite used in Holland to rear other predators is from here.
‘‘The original stock of limonicus Koppert used were from here, too.
‘‘ So they do like to keep an eye on us and we do find some exciting things from time to time but nobody here tends to have the money to do anything with it.’’