Here are some five year old long leaf pine trees where the terminals are bending or twisting awkwardly. This growth occurs when something physical breaks the terminal as they are young. Sometimes wind is to blame. There is also someone who noticed crows breaking terminals.
You’ll notice in the picture how much growth by the new terminals. Since these pines were planted on the edge of a yard, sort of residential situation, they are getting more fertilizer from grass. They are also likely in a really good spot. This extra growth also effects how these trees are bending. In this situation, you would not want to put any more fertilizer.
Mowing injury at the base causes pitch canker
This is the time of the year when we think about burning and herbicides use when we are trying to clean up hardwoods in pines. When we are preparing to burn and not enough fuel on the ground, we may need to treat individual trees. This past week, I’ve had discussions about wide-spaced injection techniques and basal bark techniques.
When we have larger diameter trees, greater than 6″ diameter, we use this technique called hack and squirt. All you need is a small hatched and spray bottle. Imazapyr and triclopyr are commonly used for herbicides which are mixed with water. Depending on concentration of herbicide in solution is how many cuts we make in the tree. If 25% Arsenal AC or 50% Chopper is used, make 1 cut into the stem for each 3″ of tree diameter. (A 3″ diameter stem will receive 1 cut while a 6″ diameter stem will receive 2 cuts.) The cut goes right into the outer bark of the tree. You spray the solution into each cut.
For hardwoods that are 6″ or less in diameter, we can use a herbicide mix with oil and spray the lower bark. This is called basal bark, thinline, or streamline treatment. We want a 20-30% of triclopyr and a 70-80% oil. You can mix this in a sprayer on a backpack or gallon sprayer. One of the questions we get is type of oil. Deisel fuel is commonly used as the oil, but the smell is not fun to deal with. Here is some information on oils and treatment specifications from UGA Extension Forester Dr. David Moorhead:
One of the foliage feeding pests Dr. Moorhead discusses at our Forestry Meetings is the redheaded sawfly (Neodiprion lecontei (Fitch)) . It is actually a broadwaisted wasp which feeds on the needles of newly established pine trees. UGA Extension Forester Dr. David Moorhead said environmental conditions are good for sawflies right now.
Longleaf pine damage from redheaded pine sawfly
This morning, we looked at a stand of 2 year old longleaf pines. The larvae of the sawflies chewed the needles back to the fascicle. There are many species of sawflies, and they are very selective in which pine species they feed. They are also treated the same way. They are very susceptible to different insecticides. Their infestations are generally localized, much like an Ips beetle. If the tree is not under stress, it can usually withstand this much damage. Some species have 1 gernation/year while others as much as 3 generations/year.
The redheaded pine sawfly has an olive green body with black stripes or a row of black spots on each side. And a large, black spot on the last body segment. Hosts of this species are loblolly, slash, and longleaf pines. They occur from Virginia to Florida and west to Arkansas and Texas.
Redheaded sawfly larvae
Some of our insecticides used do not have a long residual – maybe 2 weeks (depending on rain and sunlight). It is best to treat each tree with active infestations. However, you may see some yellowing within the needles. The female adults have an ovipositor that is serrated which allows them to saw little slits in the needles were eggs are laid. This is how they get the name “sawflies.” Yellowing inside the needles are where females have laid eggs.
Yellow on needles where sawfly eggs are laid
Chewing damage from redheaded sawfly
Sawfly damage on longleaf pine
For more information visit Conifer Sawflies on the Center for Invasive Species website.
Over the past month, we’ve been seeing different symptoms in loblolly and longleaf stands in the county. In some tree branches, we see inside needles turning brown and shedding where other trees, outside needles are turning yellow/brown. In either case, multiple issues can be associated with each symptom. What I want to show here is some longleaf needles where the inside is turning brown and shedding.
UGA Extension Forester Dr. David Moorhead says this is usually caused by a few different things. The symptoms can be associated with either a foliage disease like needle cast or an natural shedding of the older growth of needles. What we are seeing now is a natural shed. In a dry year, the tree will have one flush of growth in the season. With multiple wet years, the trees have put on more flushes of growth each year. This is resulting in a higher shedding this year. This is nothing we are concerned about. Basically, we have a higher component of older needles.
Here are some loblolly and shortleaf pines at a plantation house. We went to check trees since many have died over the past few years. Many of these trees are very old and UGA Extension Forestry Specialist Dr. David Moorhead says these pines do have a number of years where they reach and start dying. We’ve also had dry seasons (’10 & “11) followed by rain seasons (’12 – ’14) that are impacted hardwood trees and may be causing issues in pines also.
Only one tree in this stand was actually declining at this time. The needles were starting to turn red in the crown (tree leaning). At the base of this shortleaf is a foam substance with small insects around. The foam sort of disappears as you touch it. It is the result of slime flux or bacterial wetwood. This is something more common on hardwoods but can also impact pines. It is a bacterial that infects when the tree is under some sort of stress. The foam sometimes has a nasty odor. This shortleaf is well over 100 years old too.
Slime Flux and Wetwood has more information on this publication.
Last week, we looked at some loblolly and slash pines concerning the outer bark pealing. This stand is almost 20 years old and random trees appear to have this damage. The damage is only to the outside bark on not to the cambium layer (white later). We were confused about the damage since the bark was hard to pull off. UGA Extension Forester Dr. David Moorhead says he has seen this from time to time and it is from animal activity. This damage does look similar to a fungus in hardwoods called Smooth Patch which works on the outside bark. Concerning this stand, either birds but also fox squirrels have caused this damage. There may be other animals involved too. Most of the time they are looking under the bark for insects.
Are beetles a concern?
We were concerned about beetles being attracted to the damaged trees. The resin that is leaking from the wounds can attract beetles. Ips beetles are a concern since they carry the blue stain fungus. However, Dr. Moorhead says that although Ips beetles are notorious for attacking injured trees, they can also disturb healthy trees. Sometimes the resin crystalizes quickly and it’s not a problem. Ips beetles can enter high on the tree, so preventative sprays are difficult. The good news is that Ips beetles hit a few trees and leave the sight. They do not damage a stand like Southern Pine Beetle. We usually do more damage to a stand cutting down trees from Ips beetles than leaving them alone. Also, by the time we notice an Ips attack, the beetles are already gone.
Black turpentine beetles do not carry the blue stain fungus. Unlike Ips beetles, they enter the tree from the bottom. Spraying preventative for these beetles is effective. A pyrethroid insecticide, like Onyx, can be sprayed, but must be used every few weeks, because it has less residual.
Here are some longleaf pines being cut down on a plantation that are having some issues. The needles at the tops of the trees have turned brown and died back. It is a classic sign of Ips Engraver beetles. When a tree is struck by lightening, more often than not, Ips beetles will fly in and attack the tree. Ips will usually hit a few trees and then leave the area. Ips along with Southern Pine beetles induce blue-stain fungus which quickly kills the tree. The initial problem was that we were not seeing signs of Ips beetles.
Sawdust at the base of shortleaf pine is from Ambrosia Beetle
Signs of beetle attack are pitch tubes on the bark/branches, sawdust at the bottom of the trees, or galleries (beetle tunnels) inside the bark. We inspected the few trees that had not been cut down and trees that had just been cut down. (SPB enter the middle and top of the trees. Ips will enter the tree at any spot. Only Black Turpentine beetles enter the bottom of the tree.) Photo to the left is sawdust left from secondary Ambrosia beetles.
Decay on shortleaf pine from Red Heart
Without the signs of any primary beetles, we considered disease. These trees had actually showed this decline since November. Since Ips beetles do induce blue-stain fungi, this would kill a tree very fast as fungi clog the vascular system stopping water movement up the tree. We are in a hot spot for Annosum root rot in our area since we have well-0drained sandy soils. However, annosum rarely causes trouble longleaf. It is devastating on slash and loblolly. The last thinning here was done 15 years ago, and annosum generally infects following a thinning.
UGA Extension Forestry Specialist Dr. David Moorhead pointed out that the tops of these trees are flattened out (top photo). This means these longleafs have ceased terminal growth and only growing laterally. They are at the age were they naturally will develop Red Heart. Red heart is normally confirmed when the tree is cut down and we see large decay inside the trunk. Sapwood here still looks good. The best management is to salvage declining trees without damaging other trees, and maintain overall forest health.
Sign of Red Heart is resin-soaked bark
Early last week, Mark Coram and I were looking at cogongrass on their plantation. Some parts of the leaf were turning green, and we were easily able to make an ID by the off centered midrib. We also pulled up some rhizomes. The rhizomes of cogongrass are sharp from the ground. This is a very small spot – actually an average size spot. My photo does not show it all, but it is textbook shape- a small circle and moving in a line away from the circle. It was likely brought in from a harrow. They are getting close to burning and we discussed the threat of cogongrass burning hot and injuring trees.
This is true and we want to be cautious about burning cogongrass since it can burns around 850 degrees F. Georgia Forestry Commision Forest Health Specilist Mark McClure says most trees on our plantations are widely spaced and damage from burning cogongrass is not a high risk. Mark says this is actually a good time to burn cogongrass and is a good idea to burn it if we see it. This is because fresh growth of cogongrass helps when treated. Mark McClure coordinates the Task Force of the Georgia Forestry Commission which treats reported cogongrass.
If you see what looks like cogongrass, call the Georgia Forestry Commission or the Extension Office (225-4130) to get a positive ID so it can be treated at no charge to the landowner.
We were out looking at longleaf pine seedlings established on a plantation south of town. They have just planted around 12,000 longleaf pines. They are planting at 720 trees per acre. The trees are placed 6 freet from one another and rows are 10 feet apart. This will allow space for mowing for weed control. Also note that the plug is a little out of the soil. This is to keep soil from covering that terminal bud. We don’t want to be too much out of the soil for concerns of losing water either. Once the trees are established, then weed control options will be considered.
Not only do we need to follow the herbicide label and use recommended herbicides at seedling stage, we need to watch closely about our timing. We need to wait at least two months to apply herbicide over the top of long leaf and slash pines (2 inches of white feeder root growth from 5 laterals), and one month for loblolly. Here are some thoughts on applying herbicides to newly planted pines for herbaceous weed control from UGA Extension Forester Dr. David Moorhead:
- Be sure that the planted seedlings have started active root growth before herbicides are applied. Dig several seedling up and check for root growth into the surrounding soil. Cold temperature, dry soils or excessively wet soils can delay the start of new root growth. These photos (below) show root plugs of containerized longleaf seedlings. The plug on the left is a newly planted plug where root growth has not emerged from the plug. On the right, the seedling has active root growth into the surrounding soil – at this point it is safe to apply herbaceous weed control. With bareroot seedlings new roots should also be growing into the surrounding soil.
Photo by Dr. David Moorhead-UGA
- Be sure that you select the proper herbicide for the pine species you are treating. Loblolly, longleaf and slash pine each have varying tolerance/sensitivity to the various herbicides used for herbaceous weed control. Some herbicides cannot be used for some species of pines. Check the herbicide label to be sure.
- DO NOT add a surfactant to the herbicide used for over-the-top herbaceous weed control. While the Arsenal AC formulation of imazapyr can be safe applied over-the-top of pine seedlings at recommended rates, the same herbicide formulated as Chopper has a surfactant added and will damge/kill seedlings if applied over-the-top.
- Take soil samples to determine pH and soil organic levels and to determine soil texture as herbicide selection and/or rates may need to be adjusted according to soil conditions.
- Avoid treatments when seedlings are stressed from cold, dry, or excessively wet conditions.
- See the following links for specific information on applications, and herbicides:
This is a stand of improved slash pines planted in 1995 and were 4th row thinned about three years ago. Last week, I made a blog post about Japanese Fern and Chinese Privet. Here is a native shrub found in the Coastal Plain region – Inkberry (Illex glabara). UGA Extension Forestry Weed Specialist Dr. David Moorhead says that burning will keep it small in stature but it is adapted to fire. A herbicide treatment using tricolpyr would be helpful. This would also will be fine without harming grasses. For more information on forest weed control, visit the Center For Invasive Species website.