SUMMARY: With the spring weather, many pests and predators are becoming active. Twig aphids are already starting to hatch which is earlier than most years. Rust mites are very active. Cinara aphid populations may be crashing from earlier this year with increased activity from lady bugs. Be sure to be in your trees scouting so that you'll know if you need to treat and can choose the best materials for control. For more details, see below!
Spring has sprung as they say and bugs are no exception. Today I visited two fields in Mitchell County with Jeff Vance and found a lot of activity.
Cinara aphids. In one field, we've been following a heavy incidence of Cinara aphids since the first of the year. Most of these aphids are dead already from natural causes. We saw several Harmonia lady beetles feeding on them. We also found some white sap or honeydew on some of the needles. I tasted it and it was definitely sweet. There's a lot of sooty mold too on the trunks and branches -- parting gift from these pests! Below are some photos.
 |
| Most of the aphids are dead, but there is one in the middle right hand that is still alive. |
 |
| White sap or honeydew on the needles where Cinara aphids have been feeding. |
 |
| Harmonia lady beetle. |
 |
| I think this lady beetle is infected with a fungus. |
Balsam twig aphids. The aphids have started to hatch already. They are about a week to 10 days earlier than normal. I would estimate that 25% of the eggs have hatched already. I did see a dead aphid and an egg that looked like it might be dead -- black inside. A lot of rain will be hard on the aphids and some will die. A cold snap will kill many too if we have one.
However, I am afraid that since the spring is so early and it is staying warm, that twig aphids may be bad this year. Be sure to scout in fields where you treated last fall with bifenthrin products such as Talstar to make sure that you have good enough control. The warmer it is and the longer time from egg hatch to bud break, the longer the aphids will have to mature and reproduce. This may be the year that fall twig aphid controls fail us, so be sure to keep looking!
If you are treating this spring for twig aphids, you can start treatments any time . The only exceptions are Thionex and Di-Syston. With these products you need to wait until all the twig aphids have hatched, but that may be within two weeks!
Hemlock rust mites. Another pest that really likes the early spring are hemlock rust mites. In one field I was in today, the rust mite population was almost at treatment threshold. It was at 60% incidence and one shoot had at least 8 mites per needle.
Rust mites like spring and since we are having a pretty one, they will most likely be bad. They haven't been the last few years, so don't be caught off guard. Be sure to scout fields and treat for them if necessary. What are the best materials for HRM control? Horticultural oil, Envidor, and Sanmite are three of our best products. Dimethoate knocks rust mite problems down, but they will rebound. In fields with rust mites, be careful about using synthetic pyrethroids (Asana, Astro, Talstar, Wisdom, and Sniper) as these products will make rust mites worse. They may also make elongate hemlock scales worse, so only use them when necessary in the spring, or better yet, save their use until fall.
Spruce spider mites. I saw quite a few spider mite eggs today, but no mites that are hatched out yet. I do know of some folks that have seen mites crawling. If the weather continues warm, I'm sure it won't be long until they are active.
Twice stabbed lady beetle. We also found a couple of twice stabbed lady beetles active in trees that have elongate hemlock scales. Here is a photo.
 |
From this angle you can only see one of the red spots.
Still not a bad shot considering I was using my cell phone! |
What's the take home lesson with all of this? It's time to scout, of course!! Be sure to get out in your trees over the next couple of weeks to see what's active. And pay careful attention to rust mites.
