ION STAUTON, Pestec Australia

 Way back in September 2023, crop growers were looking forward to this past season.

Rural Business, had an article on page 6: Matthew Cossey, chief executive of Crop Life Australia, was quoting a Deloitte Access Economics report which read: “… without pesticides, 78 per cent of fruit, 54 per cent of vegetables and 32 per cent of cereals produced for consumption would not exist”.

Another stat revealed was: “73 per cent of the $43.2 billion of total crop production is attributable to farmers access to and use of crop protection products.”

I’m both an entomologist and a manufacturer of one of those insecticides… how do you think that made me feel? As a grower who pays a lot of money for crop protection chemicals and equipment, does that make you feel more comfortable about spending money on pesticides?

Let’s look at it.

If you spend say 25 per cent of what you get for your fruit or vegetable crop on crop protection… that is a lot less money than you lose to insects (the 78 per cent or 54 per cent quoted).

Maybe you should do your own maths: what dollars did you get for your crop, minus what you spent on insect control?

Heard about insect population explosion?

It happens.

For example, four of the most prevalent pests are aphids, thrips, whitefly and mites.

They all go through from hatched egg to egg-laying female in 2-4 weeks.

Each female produces around 100 eggs all hatching to suck, munch, mark (and spread viruses). If half of those 100 eggs is a female, that means each generation is 50 times bigger!

The third generation is 50 times bigger than the second generation… and you’re only 6-8 weeks into your crop growing time!

It gets worse.

Aphids for instance, can reproduce parthenogenically; females can give birth (no egg stage) to all females without wasting time on sex. Mites can compete with or beat those numbers.

Then there is the high chance of invasion.

Thrips feed on native vegetation including pasture, shrubs and trees.

They usually overwinter somewhere nearby because there’s nothing to eat where your crop land is vacant soil.

Soon after a green tinge appears, thrips which have been grumbling about rasping away at half-dead, brown and decaying grass go into invasion mode.

Millions of them rise as one and from altitude see your green and head for it. 

Those millions multiply by at least that 50 times we mentioned last paragraph and in another three weeks it is another 50 times bigger.

So, judicious use of insecticides is the only way you will have a crop worth harvesting. The numbers quoted are definitely valid.

The entomologist part of me wants to explain that there are more pests than those aphids, thrips, whitefly and mites already mentioned.

Diamond back moth, armyworms and other caterpillars, leafhoppers, vegetable/Rutherglen/lace bugs, monolepta/scarab/pumpkin beetles, fruit fly and those bloody grasshoppers… they all want to eat efficiently which means they just love to go to a crop that is growing exponentially and conveniently.

The manufacturer in me also wants to explain that pesticides come in three main groups.

The residual insecticides have their main use in the soil to kill eggs and larvae feeding on mostly grass/pasture roots from which the adult moth/butterfly/beetle flies to eat your crop.  Armyworms also live in the soil and then crawl directly up onto vegetable and cereal crops. These insecticides, applied to label directions have a rightful place in your shed.

The systemic insecticides course through the sapstream to kill any pest eating plant tissue. Leaf miners, codling moths, fruit fly and all other pests that get inside the plant can’t be controlled by contact spays applied to the outside of the plant.

Again, the label is the law and you need to follow the application rates, observe the withholding periods and the permitted crops.

Lastly, there are the contact sprays. (Our Py-Bo is of this type).

You should have these ready in your shed for when pest numbers are beginning to cost you or plagues arrive. They have a one-day withholding period. If you can hit them with a droplet … they die.

There is no mating; your crop is not sucked or chewed. You get to harvest it all.

Ion Staunton is an entomologist with Pestech Australia P/L manufacturers of Py-Bo Natural Pyrethrum Insecticidal Concentrate. pestech.com.au