Stemming a bug invasion
Natural solutions to turning back unwelcome invaders
A few years ago, on my way home from visiting my son in Angus, Ont., I came across a garden centre with asparagus roots for sale. I bought two dozen. When I got them home I did some research on the Internet as to how to prepare the bed for planting them and other information I might need. That first year they came up and grew beautifully. I don’t remember anything about pests or diseases.
The next spring the spears came up and I sampled a few of the bigger ones, but wanted the bed to develop so I didn’t harvest any more. Again, the spears started growing beautifully. But by mid to late June, something was very wrong. The foliage was disappearing very quickly. On close inspection I saw little black worms. They were the larvae of Asparagus Beetles. More research enlightened me about these nasty beetles. Rather than use insecticides which get into the soil and kill beneficial organisms I picked the adults off, drowning them in soapy water. The larvae disappeared when I sprayed the plants with a soapy water solution (one part soap to 40 parts water – but not detergent or bactericidal soaps.) The next year, although I was plagued by the Asparagus Beetle again, the infestation was much less and the plants remained healthy. We even enjoyed a few spears for dinner.
There are two types of Asparagus Beetle – Common Asparagus Beetle ( Crioceris asparagi) and Spotted Asparagus Beetle ( Crioceris duodecimpuncata). Common Beetle larvae feed on foliage, the Spotted Beetle larvae enter the berries and feed there. Removing the berries will get rid of the spotted beetle larvae.
Asiatic Lilies are also plagued with a beetle that responds well to the same process of control. Drown the adults and spray the larvae (that ugly black gunk) with soapy water.
I find that a lot of worms on plants like my rose bushes or the Rose of Sharon respond well to the soapy water treatment as well. After treating anything with the soapy water, leave it on the plant for 10 minutes or so and then rinse off well with the hose.
My Boxwood shrubs are also plagued by an insect. This one is the Boxwood Leafminer ( Monarthropalpusi flavus). The larva of this insect enters the leaf from the bottom and feeds on the inside of the leaf. Early on, the leaves will have blisters on the underside. Eventually the leaves will turn yellow and be smaller than healthy ones. I have a cou- ple of these shrubs that are severely infested and may need to be removed. The rest of the shrubs are healthy and able to withstand this infestation.
There are a few things one can do though to help the shrubs resist these bugs. First, encourage natural predators such as lacewings and spiders. Keep your plants healthy by enriching the soil with compost. Use mulch to help maintain moisture. Help to reduce the Leaf Miner population by pruning the foliage just after the adults have laid their eggs in May. If you see what look like gnats swarming above your Boxwood in the spring, they are most likely the adults prior to laying their eggs. One last thing, select cultivars that are more resistant such as Buxus semper-virens 'Pendula,' '‘Suffruticosa,' 'Hand-worthiensis,' 'Pyramidalis,' 'Argenteovarigata' and 'Varder Valley'.
Slugs and earwigs are other visitors that I wish would stay out of my garden. While they both eat young vegetation, earwigs also eat decaying material and insects. The evidence that slugs have been at work is the silvery mucous trail that they leave. Both slugs and earwigs hide during the day time and forage at night. They both like dark moist places to spend the day. How often have you lifted up a pot to find earwigs and sometimes a slug or two hiding underneath?
Earwigs and slugs like to hide in the same types of places – under boards, stones and debris. To help get rid of them, remove their daytime hiding places. Since slugs especially like to hide under boards, you can use the boards to trap them. Simply put down a 12 inch by 15 inch wooden board, raised off the ground one inch on wooden runners. Place the boards in an area infested with the slugs. Check them in the morning and destroy any slugs found on the board. Putting crushed egg shells or diatomaceous earth in the area slugs infest also can discourage them. The thin skin on their underbellies are easily torn by the sharp edges of the shells. Earwigs can be caught in paper tubes left in the garden and emptied into a bucket of soapy water.
No matter what type of plant you have, there is bound to be something that can attack it, whether it is an insect or a disease. By choosing our plants carefully and giving them a good start we can help them to overcome some of the pests and diseases they are prone to.
This year we had a very healthy crop of asparagus. Next year there will be a lot more to enjoy. I still keep on checking them for the Asparagus Beetle, but for now, my diligence has paid off.