There are at least two opinions on insects and things that crawl. One opinion says- spray first then ask questions. The second opinion says look first then ask if the insect identified is really a problem needing spraying or other "control" measures. The second opinion requires a little less chemical action and a little more consideration for what is going on. It may also require some changes to how the gardener gardens and how the planting areas are maintained.
In recent weeks I have been involved in both opinions as I found myself out and about actively "Looking for Trouble" . The result during a field trip to Banff was good news with no need for follow-up insecticide recommendations. Looking at trouble after spraying had been completed was the unfortunate scenario on another site where the good guys were killed first and then I was called in to identify them. Follow-up calls to my regular CBC phone in show confirmed how common this scenario is in Calgary right now on trees and shrubs where the good insects present and are being killed by the millions.
First to the slaughter scenario. A rather large looking insect- the ladybug is usually recognized by gardeners as a good guy. It eats aphids alive and polishes off large numbers in quick order. While their appetite is important the best benefit of ladybugs (also known as ladybird beetles) is that they lay masses of yellow eggs on the undersides of aphid infested leaves . These eggs hatch into hungry larvae with legs instead of wings and the wingless young are restricted to eating what they find in their immediate section of the tree. These "immature" ladybugs are more effective in aphid control than their parents because the larvae can't "fly away" as the children¹s rhyme emphasizes about the adult ladybirds.
The trouble for the ladybird young is that they don¹t resemble their parents. The larvae look more like little black alligators with small orange dots on their bodies. As they mature they go through a pupal stage just like butterflies. The pupae is the size of an adult ladybug but is dark brown-gray and looks more like a glob of bird dropping than a beneficial insect. At both the larvae and pupal stage people panic and want to spray. They become so concerned with the numbers of unknown bugs on their leaves they spray first to kill the insects and then call for reassurance . Because ladybugs reproduce slowly compared to aphids who bear live young and skip the whole egg and immature stage- it takes quite a while for the ladybird populations to reach the population explosion of aphids and a chemical spray does more to harm the ladybugs than the aphids who simply fly in from a nearby infested tree or branch to take up where their unlucky relatives left off.
It is always better to simply monitor trees and shrubs with aphids than to take action. If the aphids are washed off occasionally or even if they are allowed to build up somewhat there is a good chance the ladybirds will find them and then take action. Getting to know the looks of the whole ladybug family from egg to larvae and pupae is important so that the good guys are not inadvertently killed.