We are pretty fortunate in Alaska that we don’t have too many bugs or pests to contend with, but there are a few doosies that have hit really hard these past few years and others that have been around for as long as I can remember. This article is dedicated to spotting and treating these persistent pests.
Aphids – Aphids are amazing pests. They reproduce at rapid paces and can do an amazing amount of damage in a short time. Aphids actually bear live, pregnant young. Luckily, for our plants’ sake, they are stupid. In most exterior cases, all you have to do is wash them off the flower, shrub or small tree with a hard blast of water. Once they are off the plant, they can’t find their way back and often this hard blast of water will squish their soft bodies. You generally only have to do this 1-3 times before they are gone. You will find these pests on the new growth of a plant, on the underside of a leaf, and on the stem under a bloom. They are fat, green bugs. Most of them are born wingless but you may see some with wings if the populations have exploded.
Yellow headed spruce sawfly – These have been attacking mainly small spruce trees all over town. They can cause a spruce to lose all of its new growth and possibly turn the entire tree brown if left untreated. These can only be treated when they are chewing on the spruce. If you wait too long, it is too late to do anything for the year. We use Pied Piper to spray these pests. They will get you a quote in the spring and spray the trees at the appropriate time. This is a relatively new pest that is spreading its range in town. Once you have the damage you will need to treat for them every year. You can spot these by the browning new growth and small worm-like insects in the trees.
Leaf Rollers – These attack a wide variety of deciduous plants. The do exactly what the name suggests, they roll the leaves. This produces a very unsightly plant for the entire season, and if left untreated for several years in a row it will kill the plant. We use Pied Piper to spray these pests. They will get you a quote in the spring and spray the trees at the appropriate time. You can spot these pests either by the damage of the rolled leaves or small worm-like insects.
Slugs – Yuck. There are not many things that give me the heebie jeebies but these pests do. They are gross, slimy, fat worm(ish) creatures that leave mysterious holes in the leaves of your plants. They are nocturnal so you often do not see them chewing on your leaves. They hide under rocks or wood or other protective spaces during the day. You will often find them on the underside of one of these protections. We use Sluggo to stop them. You spread it on the ground around your plants. It is safe for pets. If you don’t like to use chemicals some people place our beer traps. Beer is irresistible to slugs (the same as it is for humans).
Caterpillars – Most people know what these insects look like. A green worm that crawl-humps along your plants. You can spot these by the damage they cause. It is similar to slug damage but you will often see the culprit on the leaves of the plants. You can use a natural spray if you like but it is also possible to simply remove the offending specimens and squash them. This is often enough to prevent them from causing too much harmful damage to your plants. One thing to note is that if the worm has a j-hooked tail, it is a sawfly not a caterpillar.
Thrips – Depending on what you grow, thrips seem to be less common than the above pests. They are tiny pests. They love doing ornamental damage to buds and blooms – especially white blooms. They can also do damage to the leaves of a plant. You will often find them on the back side of a leaf. You can spot them by distorted growth. These can be a bit harder to treat since they often have themselves tucked inside the blooms. You can try spraying them off like aphids to knock back the populations a bit.
This is definitely not a comprehensive list of pests for Anchorage. I would suggest taking any specimens in to Cooperative Extension. They will identify the exact pest for you and give you suggestions for treatment. Happy Gardening!