Category Archive: Insects

The hungry little caterpillars

By James Wall

There are times when some of us want to destroy caterpillars. I know those ones on the broccoli in February are really annoying. There is however a couple of nurserymen who love caterpillars on their plants. In fact they grow them especially to feed the caterpillars. This is what I discovered behind the scenes at the Melbourne Zoo. It is all part of the butterfly enclosure and its ongoing breeding cycle that takes place so we can enjoy these wondrous creatures everyday of the year.

Host plant for butterfly to lay eggs on

What you need to do as a butterfly plant grower at the zoo, is reproduce the 6 or 7 different plants, each one for the 6 or 7 different varieties of butterflies bred. You see they are very fussy and each type of butterfly will only lay their eggs on a particular plant. If the butterfly is a tropical variety, then the plant needs to be a tropical plant, meaning growing it in a greenhouse for many months of the year here in Melbourne. Now it is no good having one big batch of plants ready at once. You need to have some ready for the butterflies, some half ready, and some freshly cut back so they will be ready in a couple of months time. No plants ready equals no butterflies, so the pressure is always on, especially in winter. It’s a bit like growing lettuce all year round in your vegetable garden. You don’t plant a whole lot at once. Eight plants every second week and you will have lettuce all year round.

Some butterflies like poisonous plants like oleander. Apparently the caterpillar themselves will contain some of these toxins, and can make a predator that eats them very sick. They will think twice before eating that same colour caterpillar again. Its sort of weird how this one being eaten now, will save one of his mates in the future.

well chewed lemon

One of the plants grown is the common old Lisbon Lemon. This is used to reproduce the Orchard Butterfly, its caterpillar pictured above. It’s not the most spectacular butterfly, but of course the spectacular butterflies eat the much harder plants to grow. Of course a lemon tree chomped like the one pictured  actually means a job well done.

Plants are placed in the main enclosure which is at a beautiful temperature if you like a 28 degree average. Once the eggs are laid, the plant is taken into another enclosure where caterpillars hatch and begin to eat the host plant. The caterpillar then forms a pupa or chrysalis which is like a cacoon inside which it forms into a buttefly. Often in the wild, this pupa is well camouflaged. At this chrysalis stage they are removed from the plant and hung in their own little box made of insect screen walls so as to protect them from potential predators like rats.

They are then released into the main butterfly enclosure and as we saw, midweek mums with prams, toddlers and lattes emerge in large flocks, all enjoying the magnificence of the beautiful butterflies.  For me there was the extra appreciation, as before this day, I had never considered the laborious horticultural process that helped make the butterflies grow. Each butterfly only lives for about a month, But their life cycle goes on and on forever.

big juicy and happy caterpillar

Chrysalis stage

Protective screened area where butterfly hatches

Orchard butterfly that enjoys lemon tree

LINKS:

TEN STEPS TO A BUTTERFLY GARDEN

BUTTERFLIES OF THE MELBOURNE AREA AND THEIR FOOD PLANTS

Slightly broken butterfly on slightly broken palm leaf

Thermometer showing min max temps in butterfly house

The Grapevine Moth

By Bonnie-Marie Hibbs, first published in her gardeners notebook.

Phalaenoides glycinae, Grapevine moth has been spotted on a few different plants throughout the summer months.

The caterpillars have very distinct colourings and patterns, which makes them very easy to identify.

These little guys grow to a length of 50mm with a black and white abstract pattern on the upper and underside of their body. Their body is covered in small white coloured hairs with fuchsia coloured stripes near their feet and their back end. Their face is gold-yellow with black dots.

Unfortunately these guys are NOT a beneficial bug. The caterpillar will feed on a variety of plants such as Australian natives, Fuchsias, Boston ivy and both ornamental and fruiting grapevines. Usually the caterpillars and larvae will feed on the undersides of the foliage, so if you happen to spot some on your plants make sure to check the underside of the foliage. If a lot of larvae are present on a plant they are capable of defoliating a vine or attacking any developing bunches of grapes on your vines.

I have managed to find up to 10 caterpillars on the one plant. Pupation will occur in any leaf litter that may surround your targeted plants or within the soil.

 After the caterpillar has entered its pupation stage, a small black moth will emerge. The wingspan of the moth is 50mm with yellow markings on both wings and at the end of the body is a collection of orange hairs. Fortunately, the moth doesn’t cause as much of a problem as the larvae and caterpillars.

When it comes to control you can either use a chemical based spray or can try an organic control method.

You can remove the caterpillars and larvae by hand and dispose of them. Otherwise, natural predators will feed on these guys, such as birds, beetles and wasps. One beetle that loves to feed on the Grapevine moth/caterpillar is the Shield bug, which in Latin in known as Oechalia schellembergii. The shield bug likes to feed on the body fluids of the caterpillars and larvae thus eliminating them.

An effective bacteria called Dipel

You can also use Yates Dipel to kill caterpillars. Dipel (Bacillus thuringiensis), a naturally occurring bacteria. Dipel does not kill caterpillars immediately. Once a caterpillar eats treated foliage, it gets a pain in the tummy and stops eating, but may take up to 3-4 days to die and drop from the leaf. This is a low toxic, organic soluton. It is safe for bees, ladybirds, birds, fish, mammals & pets.

 


 

 

 

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