Pine Bark Coming Off?

Slash-LoblollyPines 012

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.

Slash-LoblollyPines 011

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.

 

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Filed under Forestry, Wildlife

Morninglory ID

There are many species of morninglory weeds to learn in the field. We need proper identification for control.

Why is this important? Not all morningglories are controlled equally by certain herbicides. Here are a few examples:

  • Gramoxone (paraquat) is generally good on most morningglory species but not smallflower. 
  • Basagran (bentazon) is generally not effective on most morningglory species but will control smallflower.
  • Staple (pyrithiobac) is generally considered to be an excellent morningglory herbicide but not on tall.
  • 2,4-DB is less effective on pitted morninglory than other species.
  • Aim (carfentrazone) is considered a good morningglory herbicide but not on smallflower.

Here are some photos of morninglory UGA Extension Weed Scientist Dr. Eric Prostko shared from LSU and Virginia Tech.

Entireleaf-MG

Ivyleaf-MG

Palmleaf-MG

Pitted-MG

PurpleMoonflower-MG

Red-MG

SmallFlower-MG

Tall-MG

Cypressvine-MG

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Filed under Weed Science

PGR Management & Cotton Varieties – 2015

We generally make PGR determinations by length of 4th internode, height to node ratio, nodes above white flower, and also environmental factors, like rain/drought. Variety also plays a role, and here is some thoughts on new varieties from UGA Extension Cotton Agronomist, Dr. Jared Whitaker:

Cotton variety also plays a role in making proper PGR decisions since some varieties need to be monitored closely and heavily managed while some are sensitive, and overuse may negatively impact growth and development, and ultimately yield.

Because of potential differences in PGR requirement among varieties and due to frequent release of new commercial varieties, research is needed to help understand differences between varieties with regard to vegetative growth potential.

Research conducted in since 2010 has investigated the response of various varieties to two different PGR regimes (cotton which was not treated with PGR and cotton treated with mepiquat chloride three times (applied at initiation of squaring at 12 oz/A, at first bloom at 16 oz/A, and two weeks after first bloom at 16 oz/A)).  Growth parameters, particularly end-season plant height, along with lint yield and fiber quality were used to assess the growth potential of a variety and document the impact a heavy PGR regime has on development and yield.

Data collected each year is used to fit varieties into one of four particular classes of variety responses to PGRs.  The first class contained varieties with the most vegetative growth potential, and would require PGR applications in almost all situations.  The 2nd class contains varieties with similar vegetative growth potential of the 1st class, yet are more responsive to PGRs or may have earlier maturity.

The 3rd class contains varieties in which could require PGR applications, however initiation of PGR applications prior to bloom is not generally necessary and could result in premature cutout, especially in dryland conditions.  The 4th class contains varieties which may need no PGR applications or in almost all cases not applied prior to bloom.

This grouping of varieties into classes was developed to simplify PGR decisions based on variety and help growers make more education decisions when planting varieties for the first time. When a new variety is planted, PGR decisions could be based on its PGR classification due to being in the same class as a more familiar variety or because it is in a different class than a familiar variety. This system was also developed so that future investigations of PGR needs of new varieties can be more easily evaluated and quickly determined.

Below is the relative PGR classification chart which has been updated with information from 2014:

UGARelativePGRRequirements-2015

 

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Pre-Bloom Irrigation In Cotton

Cotton-Irrigation 007

We’ve had some rain the past few days and even some in the northwest part of the county that is usually dry. Today I was in the central part of the county and fields were still wet from rain yesterday. Although irrigation requirement is higher for blooming cotton than for pre-bloom cotton, stressing cotton during squaring has more negative effects than we realize. Cotton does not rebound if stressed from no irrigation through squaring. UGA Extension Cotton Agronomist Dr. Jared Whitaker conducted research on this using the UGA Checkbook Method where the pre-bloom irrigation was eliminated and they had no difference in non-irrigated cotton. The reason for this is that cotton grows vegetatively and reproductively at the same time. During its vegetative growth, cotton is setting nodes. If it is stressed during this time, less nodes are set. Below is a graph showing the research and UGA Checkbook Method.

ImpactofPre-BloomIrrigation-J.Whitaker-2012

UGACheckbookMethod

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Filed under Cotton, Irrigation

Sidedressing Cotton

As cotton is squaring throughout the county, we need to also think about sidedressing. Here are some thoughts on sidedressing from the 2015 UGA Cotton Production Guide.

Nitrogen (N) Management

N can be very difficult to manage. Base N rates recommended by UGA Soil Testing Lab according to yield goals are blow:

YieldGoal-2015

These rates should be adjusted according to other factors:

  • Increase N by 25% if – Deep sandy soil, cotton following cotton, history of inadequate stalk growth.
  • Decrease N rate 25% if – Cotton following peanuts or soybeans, cotton yellowing good stands of winter legumes, history of rank/vegetative growth.

UGA Extension Scientist Dr. Glen Harris says our N rate should be applied in split applications since N is mobile in the soil. We want to apply 1/4 to 1/3 of recommended N at planting and the reminder at sidedress. Sidedress N between first square and first bloom. (If cotton is growing slow and pale green, sidedress more towards first bloom.) Sidedress N can also be applied as foliar treatments or through irrigation. No N should be soil-applied (including pivot) after 3rd week of bloom.

Phosphorus (P) & Potassium (K) Management

P & K need to be maintained in the upper medium range by soil testing. All of the P requirements should be applied preplant since it is relatively immobile in the soil and important to seedling growth. K should also be applied preplant on all soil types including Piedmont, Coastal Plain, and Deep Sand soils. Split applications of K have not proven to be effective ton Tifton type soils. Recent field trials in GA have focused on additional soil-applied K during N sidedressing versus foliar K during peak bloom (4 weeks bloom). Dr. Harris says results on Coastal Plain soils indicate that foliar K may be more effective than sidedress K in improving yield.

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Stemphyllium Leaf Spot

Currenty, foliar K applications should automatically be considered on deep sands, low K soils, high Mg soils, high=yielding conditions, short season varieties and where K deficienes have occurred. Cercospora, Alternaira and Stemphyllium leafspot have all been linked to K deficiency. They are secondary to K deficiency. Corynespora leafspot does not appear to be linked to K.

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Filed under Cotton, Fertility

Plant Bugs

Last season, we had more plant bugs in cotton than we would normally be talking about. Cotton is now squaring and reports of a few plants are coming in. There are not many reported; however, scout Andrew Taylor took this picture of an adult plant bug.

PlantBug-Adult-A.Taylor

Adult Plant Bug – Photo by Andrew Taylor

We still do not need to spray if not needed. Sometimes, less retention can occur even when plant bugs are not present. We need to monitor both square retention and plant bugs. Plant bugs are mobile and can move in and out of fields fast. They can be present and not causing square loss. Here is a threshold from UGA Extension Entomologist Dr. Phillip Roberts:

Threshold

TarnishedPlantBugThreshold

 

 

Here is a photo of an adult plant bug taken by scout Andrew Taylor. He is also reporting some “black flags”.

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Filed under Cotton, Entomology

Lesser Cornstalk Borer

Grady County Agent Brian Hayes has been getting reports of Lesser Cornstalk Borer in peanuts with the temperatures hitting the triple digits. With less rain in the forecast, this provides an environment for an LCB outbreak. Last year was a bad year for LCB in many years. Some folks in Thomas County have sprayed for LCB also. The only product that UGA currently recommends for control is granular Lorsban. UGA Extension Entomologist Dr. Mark Abney and Brian Hayes put out a LCB trial last year and found couple of promising products. Below is some of the data from that trial I wanted to share from Brian’s blog:

LessercornstalkBorer-M.Abney-2014

LessercornstalkBorer-M.Abney-2014(b)

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Filed under Entomology, Peanuts