By GEOFF MIERS
Following the rain we are about to experience a population explosion in garden pests with the home gardener needing to consider a range of both chemical and alternative control methods.
It would be nice to make an exception in our necessary war against these invaders: This photo by Dr FIONA WALSH shows an Ayepe-arenye (Yipirinya caterpillar) with head left, tail right. They are a major totem for our town area.
As for the rest, it is essential that the gardener rotates the control methods used as pests can quickly develop a tolerance if the same chemicals are constantly used.
Rotating between using chemical control solutions, biological or environmentally friendly alternatives and old fashioned methods may prove to be the best option.
Grubs and caterpillars of many varieties, a myriad of ants, and of course grasshoppers are the main pest challenges confronting gardeners at the moment.
Of course don’t forget lawn grub or army worm and African Black Beetle eating out lawns, white lace scale particularly on callistemons, mealy bug everywhere and aphides that are starting to erupt in numbers.
On grasshoppers that are descending in their thousands and defoliating many plants physical isolation of plants, contact sprays and a new alternative biological control are the real options to manage them.
It is worth noting that once the grasshoppers decide to attack a plant they will keep at it unless you take action. They often keep going until they literally kill the plant and generally the plant never recovers.
Please note there is no product that will effectively deter them long term. Home made recipes using grasshoppers, garlic, etc need to be literally applied ever day or two to deter as does derris dust.
The best immediate solution is to find where the grasshoppers have settled at night and either spray the entire area or alternatively go out at night armed with a torch and a pair of secateurs. They just sit there as you approach and its easy to catch them or simply cut them in half.
Some people are purchasing mosquito nets traditionally put over your bed and they simply hang them over the plant needing protection. You can purchase insect blankets for $45 and crop protector sheets for $34.
Spray with Carbaryl, Malathion or BugMaster for an immediate knock-em-down effect. Pyrethrum will work on the young hoppers but is less effective against the mature adults.
Looking for an alternative then consider the CSIRO produced product called Green Guard.
It is a biological, environmentally friendly product based on a fungus called Metarhizium that is suspended in an oil solution allowing the fungus spore to survive for up to four weeks.
This product is only available from Elder Rural Services and Landmark and will only be ordered in on specific request once orders have been placed. Costing around $60 to $65, it is dearer than chemicals however it is the ideal solution for those who prefer not to use chemical pesticides.
With lawn grasses growing vigorously, many shrubs experiencing an autumn growth spurt and an increasing number of leafy vegetables being introduced into the vegetable garden a range of leaf eating caterpillars, loopers and grubs are emerging.
With extreme outbreaks of these pests the need to resort to chemicals to limit significant damage maybe necessary, however there other options.
Physical barriers, traps and deterrents can all be effective control methods and can be used in combination with other chemical and non chemical methods.
Hessian wrapped around a cedar tree will see the White Cedar Moth caterpillar hide there daily making it easy to dispose of them. Blue zapper night lights can kill off adult moths thus limiting egg laying while white egg halves placed in the garden will deter the white cabbage butterfly.
As an alternative consider using the biological control Dipel. It is a favourite for many organic growers. Dipel is a dormant bacterium that is activated by the water. Dipel is environmentally safe and is harmless to humans, animals and birds. It is target specific, it only affects grubs and caterpillars.
Dipel needs reapplication every five to seven days as when exposed to intense sunlight it can break down quite quickly. I recommend applying two to three applications over 18 to 21 days.
Dipel is not affective where overhead water is applied daily, it is washed off. I am using it now on young citrus trees to keep the citrus butterfly caterpillars at bay. If using it on lawn grubs for example water the lawn well and then turn the water off for three to four days after spraying.
Another environmentally friendly alternative on the market is called “Success.”
It is derived from natural bacteria found in soil. In 1982 a research scientist was holidaying in the Caribbean and visited an old abandoned rum distillery on a tiny tropical island and came across a spot in the jungle where it was deathly silent.
“In a climate where the incessant buzz of insect life drones for 24 hours, the quiet was deafening for the scientist.” Intrigued the scientist took soil samples home, tested them and discovered a bacterium living in the soil that controlled certain insects.
Success Naturalyte was formulated using this bacteria, and is so called because of its highly successful performance as a natural insecticide.
From scientific data I have received this new product is a fast acting natural insecticide with the efficiency equivalent to synthetic products. It has low toxicity to beneficial insects such as ladybirds, and to birds, earthworms and mammals.
It controls a wide range of grubs and caterpillars including the cabbage white butterfly the diamond back moth (cabbage moth) and heliothis caterpillars that can affect tomatoes, potatoes, lettuce and sweet corn. It is also affective against tomato leafminer.
With the range of grubs and caterpillars it is effective against one would assume it would also be effective against the lawn grub.
Although this product is not systemic following application it does however move through the leaf surface via “translaminar movement” making it resistant to UV light and rain, once the spray has dried.
Talking to a research scientist it is said to be affective for three weeks after application and in fact he only had to spray twice in one season to keep the grubs under control.
However with many pest control methods repeat applications are most effective if applied as new infestations are likely to occur. This may occur every 10 to 14 days.
Once the temperatures drop below 30 degrees to be safe the home gardener can again use oil sprays as they are effective against a wide range of insects. The oil sprays simply smother the insect and they quickly die.
With bad outbreaks of mealy bug, squash with the fingers, jet them off with sharp jets of water, prune off heavily affected branches or use oil sprays with a range of other chemicals.
Chemical and oil sprays require repeat applications as the mealy bugs are often in clusters and the ones underneath are initially protected from any sprays applied.
For the complete series of these gardening columns, starting in the Spring of 2020, go to the Features button on the home page’s menu bar.