Scouting For Bugs

It has been yet another tricky couple of weather weeks in our Montana spring! I think back to when my two boys were young, and we had the neighborhood Easter egg hunt at our house each year. Looking back over the photos, some years the kids were in cute Easter clothes and some years they were wearing snow suits. Back in my college days in Bozeman (we don’t have to say how far back that was) it snowed 2 feet on Easter weekend. Yikes!!

This past week’s cold was not as harsh as the cold snap earlier this month. Outdoor plants that have been coming on with the weather are still tightly budded and can generally withstand the cold. If your forsythia or sandcherry are blooming the blooms may fade sooner. If your hosta tips are peeking up they may have been a bit nipped in the cold, but they will push through when it gets warm. We are still waiting to see if plants were damaged in the early October freeze. More on that as we see how things leaf out.

I mentioned the idea of scouting last time. It seems like a good time to make a list of pests to scout for. Let’s review the basics of pest control. ALWAYS identify any pest and research their lifecycle so you can determine the best time to treat. The younger the stage of an insect’s life the more vulnerable they are. It doesn’t do you any good to spray if the bugs aren’t out yet. Keep in mind that most insecticides work as contact killers by getting on the bug, so the bug must crawl through it, eat it or be directly sprayed for the insecticide to be effective. There are a few insecticides that can travel through the vascular system of a plant and are most effective on bark boring insects and insects that eat parts of systemically treated plants.

Every spring we end up with aphids on some of our plants. Green ash, and snowball viburnum are a couple varieties that always have aphids but generally the damage is only cosmetic. I hand pick the aphid infested leaves and put them in the trash as the snowball seems to put out a second round of leaves that the aphids don’t seem to bother. Unless you are looking for an extra excuse to be out of the house that method is probably not on your agenda. Our first instinct might be to spray insecticide, but if you can resist that urge keep in mind that early aphids are food for other ‘good’ bugs such as lacewing and ladybug larvae as well as food for birds. When deciding if you need to treat, please consider your personal pest threshold along with consideration of the threshold of harm to your plant. Integrated Pest Management is a theory of identifying your problem and deciding how to treat. That goes hand in hand with the idea of using the least toxic option for treatment. Using aphids as an example, your treatment choices include, do nothing, instant black death, eco-groovy or somewhere in between. Knowing that there are dozens of kinds of aphids with reproductive cycles ranging from live birth; reproducing offspring in a few days, to egg laying cycles as fall begins. That means repeated treatment is needed to make a dent in the numbers that make it to the stage they can winter over for next year.

Instant black death is the use of non-selective insecticides that kill most any bug it touches, good or bad. Repeated applications, which are needed for aphids will end up killing all the good bugs and bees. The in between options of oil sprays, diatomaceous earth and insecticidal soaps are less harsh but will still help reduce aphid numbers. The most eco-groovy thing to try for aphids is to spray the underside of the leaves and branches with a vigorous stream of water but you need to do it every day for 2-3 weeks to make a dent in the reproductive cycle. You need to start any aphid treatment before they curl the plant leaves. It is harder to get treatment on the bugs if the leaves are curled.

Oystershell scale is another damaging pest that can get away from you before you realize. Scale in general is harder to treat as scale insects create a hard and or waxy covering that protects the female and eggs. When the eggs hatch, usually mid to late May depending on the weather, is the time to treat to get the best knock down. All Season Oil sprays are effective at crawler stage as well as pyrethroid based products. Pyrethrin insecticides are developed from marigold flowers but they are a non-selective treatment so try to keep the spray directed at your problem. Infestations of oystershell scale are easy to spot as you can see from the photo. Scale and aphids are both chewing and sucking pests. Oystershell scale on aspen or other plants, left untreated, can weaken your trees or shrubs, and make them susceptible to other insects or disease.

Now on to disease, specifically powdery mildew. Cool wet conditions are the perfect set up for powdery mildew and other fungus. Once you see the problem it has already gotten ahead of you but you will still want to treat. If you know you will have a problem with certain plants in your yard like roses, ninebark, veronica, salvia or lilac, a pretreatment of a systemic fungicide could be your friend. Also keep in mind that early morning watering allows your plants to dry out during the day before the cool of the evening. Check your irrigation to keep sprayers off the foliage of susceptible plants.

We have also had reports of lilac blight in our area. Montana State Extension has a MontGuide for growing lilacs in Montana. You can view and print here: http://carbon. msuextension.org/documents/ yglilacs.pdf Lilac blight is caused by the bacterium Pseudomonas syringae and generally gets started during cool wet spring weather. It can infect newly emerging shoots, flower buds and leaves. The initial symptoms look like you overwatered the plant with water-soaked spots that progress to black leaf spots and shoots, misshapen leaves, drooping and die back. Several steps are needed to combat lilac blight because it is like fire blight in that it can be spread by wind, rain, watering, insects or pruning tools. It winters over in plant debris, soil, weeds, diseased cankers, and healthy plant tissue, so good yard clean up practices and tool disinfecting is needed. Remove and destroy diseased plant parts and disinfect your pruner with each cut you make. Thin your lilac for good air movement and keep the irrigation from spraying the leaves. This is another situation where you need to spray before you see any symptoms and repeat spray at the 7-10-day intervals recommended on the product label. You can spray the stems before the lilac leaves are out to get a good coverage on the stems and continue to spray all sides of the leaves as they emerge. Iowa State Extension has a user-friendly publication: Lilac Bacterial Blight. Not to discount other plant information you might find online, Extension publications are always a good source for information.

Even with the crazy weather, we are landing multiple trucks of new plants each week. We have also started some tomatoes, peppers and other veggies in 4” pots that will be ready when it is safe to plant with more varieties coming in before Mother’s Day. We just unloaded a truck of shrubs and trees on Friday and have more coming on Monday, as well as wintered over plants waking up and reminding us why we love to garden. Gardening is hopeful, relaxing, and good for the soul, and most of us are eternally optimistic every year. Oh yes, there are microbes in the soil that promote good people health and being outdoors lets you take advantage of the sunshine.

feel free to call ahead to check selection or prices. We are happy to offer curbside pickup and are taking all recommended measures for social distancing. Where better to shop than outside in the sunshine!!