ITS STILL JUST DIRT APRIL 2022 by Angela Lassam

Everyone remembers the trees being stripped of their foliage and not being able to sit under a big Maple tree for shade, even finding it hard to go for a walk in a woodlot without being bombarded by small brown beads – yes it was the Gypsy Moth caterpillar munching away in the tree canopy. If left uncontrolled our trees and gardens will suffer dramatically.

The Gypsy moth or its new name ‘spongy moth’ was renamed because of its slur towards the Romani population as it is considered a pest. It was reintroduced to Eastern Canada arriving in soviet freighter.

After the winter when the leaves start to open on a tree the eggs will hatch and become larvae (caterpillar). The newly hatched larvae spin a fine silk thread and it is blown in the wind to infect other trees. They grow very quickly consuming up to one square metre of leaves in a short time and it is during this time we notice the devastation they create. The caterpillar is very easy to see when fully grown. It is dark brown and hairy with a row of red and blue dots. After pupation the male moth, brown in colour will fly between trees seeking the female. Its lifespan is only one week. The female moth which is a cream colour is flightless. She is very easy to see on tree trunks. She lays eggs that look like creamy sacs. There can be as many as 1000 eggs in a sac and many sacs can be seen on the trunks and limbs where they overwinter.  The cycle of the gypsy moth starts again.

There are some ways to reduce their population. When the leaves are just forming in May a bio-pesticide BTK can be sprayed on the tree as far up as you can reach. Read the instructions carefully before applying. Wear protection as suggested but it is harmless to humans as the solution has bacteria specifically for insects.

The alternative is to wrap the trunk with a band of burlap 18” wide. Tie it with string round the middle and fold downwards to create a pocket for the caterpillars to crawl into. Remove them daily into a bucket of bleach and dish soap and dispose of later. Use gloves and be careful as the hairs on the caterpillar can cause severe irritation.

Another way is to carefully scrape the egg sacs off the tree and dispose the same way as caterpillars.

There is some happy news that within three years of a severe infestation it is reported they succumb to viral and fungal pathogens.

Another problem in our garden is a tree that can be found in woodlots and many established gardens. It is the Black Walnut tree. If you have moved into a new home you may have one in your garden. They grow quickly and give a large shade canopy but it nothing will grow under it. A chemical called juglone can be found in all parts of the tree. The fruit (nuts), leaves and roots all leach juglone into the soil. Leaves and nuts should not go into the compost and the roots of this large tree make an area of 50’ from the trunk tainted with juglone. Plants will be stunted, have yellow leaves and poor flowers. There are plants that are not susceptible to its toxicity. Ones well known to gardeners are hostas, hollyhocks, astilbes, purple coneflowers, chrysanthemums, snowdrops and grape hyacinths. Also forsythia, mock orange and yucca will do well. Once any flower has been planted under a black walnut tree it cannot be transplanted in another area as the juglone can live on in it and taint the area around it.