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Caterpillars launch their attack on my garden !!!

By Ben Sims
27 August, 2020

Food scraps or free food.JPG

So whilst recently reading bedtime stories to my child there is one that recently became a reality, a nightmare in fact and it was playing out in my potato patch and there wasn’t just one of these bloody things there were more than I have ever seen in my life in the one backyard!! It almost seemed like all the caterpillars in the area had a meeting and then launched a not so covert operation on my beautiful patch of potatoes. They had a bite of pretty much of everything but thought no we really like potatoes.

What was interesting is they started on the natives and denuded my beautiful Scaevola porocarya and then eventually all congregated to my potatoes and literally fattening up to what seemed like double in size before forming a cocoon to come out as ??? a beautiful butterfly ? nope,  a moth !!!  yep and thanks to Jean Hort and the guys on the Insects of WA page on Facebook page I know exactly which one. The Black and White Tiger moth or if we want to get scientific about it Spilosoma glatignyi. The black and white tiger moth is native to Australia which is one of the reasons other than educating my child on her favorite book in real life to why I did not reach for the Dipel.

The other thing is that pretty much excluding one potato crop and a native plant the rest of my garden had not just survived a plague of caterpillars but was still thriving. This is a particularly good reason to plant diversity and include a good balance of natives (mainly natives please, exotics and edibles in the one garden.

My first reaction was these bloody things are destroying a beautiful crop but then I thought it has already had 3 months to grow and if the caterpillars are all in cocoons soon then it might have another 2 months to grow and recover anyway so that’s potentially 4-5 months of time to grow free of these hungry not so little guys. 

If I was going to use anything it wasn’t going to be a chemical agent because caterpillars can be deterred by things like chili sprays as their guts are actually quite sensitive and if you want to send them to a better place then there is a well-known bacterial agent you can use. Dipel is apparently safe to everything apart from caterpillars and is a bacterial agent Bacillus thuringiensis that really upsets the guts of caterpillars but does not kill them immediately. So, it is a natural occurring agent that has been isolated and not a chemical one. 

The one major thing that people don’t realize is that with pest control you don’t only need to understand the ID of the particular pest but also what eats that pest because they can be killed also and certain things like heavy metals(Lead) or polar organic chemicals(DDT) get stored in the insects tissues and actually increase as they work their way up the food chain by a process called biomagnification. This basically means that say if a bird eats 1 caterpillar and it has 1 unit of chemical in it and the bird then goes to eat 20 caterpillars that bird now has 20 units of chemical in it. Then say a snake eats 5 birds then the snake now has 100 units of chemical in it and then an Eagle eats 5 snakes then the Eagles now has 500 units of chemical in it!!!!! The Eagle does not stand a chance and probably not the snake either.   

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We have an upcoming podcast coming soon and I was not planning on approaching any chemical companies for sponsorship anyway. We will not take money if it does not align with our brand and values. 

Ben’s Garden only supports the use of chemical agents if there is no other practical alternative and we encourage you to understand and appreciate ecology playing out in your own garden. You have got a free outdoor classroom to teach the kids about some of their favorite stories in real life.