April 2021 – 1st Edition
Developing Pitch Canker-Resistant Pines
Introduction (from Mike Cunningham, PhD, VP Global Product Development)
Pitch canker incidence has been on the rise over the past few years. Many more ArborGen customers are requesting pitch canker-resistant slash pine families. We work with the University of Florida Cooperative Forest Genetics Program to screen slash families for pitch canker-resistance and use that data to provide guidance to our customers on the best families to use. We are now cooperating with Dr. Jeremy Brawner also at the University of Florida on a new project to improve on pitch canker resistant slash pine families for the future.
Wanted: Pine Pitch Canker
Jeremy Brawner1, Tania Quesada2, April Meeks3, Kathy Smith2,4 Kathleen McKeever4, Andrew Sims2, Gary Peter<sup<>2
1 – U. Florida, Department of Plant Pathology, 2 – U. Florida, School of Forest, Fisheries and Geomatics Sciences, 3 – Rayonier, 4 US Forest Service
Concern expressed by industry partners of the Cooperative Forest Genetics Program (CFGRP) and the Forest Biology Research Center (FBRC) at the University of Florida led to a USDA funded project to develop pitch canker tolerant slash pine. The project will inoculate a diverse range of slash pine families with a diverse set of pitch canker isolates collected in stands from Texas to Florida. Seedlings will be vegetatively propagated at ArborGen’s Summerville nursery to produce clonally replicated progeny trials for disease resistance screening. The team is currently collecting samples from pitch canker infected southern pines from across the southeast to provide a diverse set of isolates for the screening. Parents and progeny will also be genotyped to create a genome-based selection model to predict the resistance of individuals that have not been screened. Validation of the model by screening untested families is planned. ArborGen will assist with the establishment of demonstration areas for longer term comparisons of resistant and susceptible clones. Our work fits into a larger USDA project that will develop systems for pathogen identification for the National Plant Diagnostics Network and develop prediction models for Fusarium resistance in pine and sweet corn breeding populations.
If you have pitch canker infected stands, please send an email to the project team and they will contact you to arrange an inspection or collection; Email – firstname.lastname@example.org.
Pitch canker, caused by the fungus Fusarium circinatum, affects a wide range of pine species as well as Douglas-fir (Pseudotsuga menziesii). The disease was first reported in 1946. It was considered a primary disease of pines in the southeastern United States, although it most likely originated in the Mesoamerican center of pine diversity. In the southeast, the disease has been more problematic in slash pine (Pinus elliottii) than other pines and its incidence increases with fertilization. Over the past 20 years, pitch canker has become problematic in various countries where pine is planted as an exotic. Pinus patula forests in South Africa are being replanted with pitch canker resistant hybrid pines and the disease is impacting the Pinus radiata nurseries and forests in California, Chile, Spain and France.
In southern pines, trees infected by the pathogen often develop symptoms that are associated with copious resin exudation from lesions on stems, branches or cones. Dead branches with white resin staining are the most frequently observed symptoms and this ‘flagging’ is particularly evident following storm or hurricane damage to stands. The disease is controlled by fungicides in nurseries where the pathogen can cause extensive seedling mortality. Following establishment, losses from pitch canker-induced mortality are readily observable; however, subsequent impacts on growth are not well quantified. The development of symptoms at mid-rotation following investments in weed control, fertilization and thinning is particularly problematic where lesions on the main stem often lead to defects that result in the downgrade of sawlogs into pulpwood and significant yield losses at harvest. The University of Florida CFGRP and the FBRC are actively working to deliver genetic and silvicultural solutions to address pitch canker in managed southern pine plantations.
Webinar Next Wednesday, April 21st @ 12PM EDT
Spend an hour with us and find out how to:
- Have the most options at harvest time whether the timber market goes up or down
- Invest an extra $1 / acre will yield and extra $16 / acre down the road
- Improve productivity and value for clients or your family
Seats are limited so be sure to grab your spot before they fill up!
Here’s the schedule:
NC / SC / VA April 21 @ 12pm
ARK-LA-TX May 5 @ 12pm – SAVE THE DATE!
AL / MS / GA / FL – May 19 @ 12pm – SAVE THE DATE!
Site Prepped and Planted – What’s Next?
You’ve invested in the best seedling genetics for your land. So now what?
Our forestry professionals have put together some recommendations for making sure your seedlings have the best chance for success. If you have any other questions, make sure you contact your ArborGen Reforestation Advisor. Remember, you will reap the rewards of superior growth and stem quality when you practice good silvicultural methods and, ultimately, better return on your investment.
Goals for your seedlings in the first year are:
- Rapid root system establishment throughout the soil profile
- Terminal buds above the competing vegetation and animal browse line
- Quick growing seedlings (height and stem diameter) in order to be large enough to resist and withstand insects and other damaging agents such as fires, cows, deer, wind, hail, ice, snow, etc.
Top 10 Tips to Achieve Those Goals:
- Apply herbicides to control weeds – the #1 enemy in a Pine seedling’s first year. Inspect the stand in late May or early June for a new crop of weeds even if you applied herbicide in late winter or early spring.
- Ask a professional which herbicides are suitable to achieve the complete control you desire for your location and help you choose the correct application method and time.
- Inspect the planting site for emerging Pine from seeds left in place after harvesting. These are harder to control because you’ll have to direct spray a herbicide onto the volunteer Pine seedlings without getting spray onto your newly planted seedlings.
- Don’t let your seedlings become deer food. Monitor closely for signs of heavy browse on winter shrubs and vines near seedlings. Sites overpopulated with deer will browse on Pine seedlings if there is not a better food source present.
- Inspect your seedlings periodically to ensure that no pales weevil activity is present. Look for stem girdling at the soil line on seedlings that show symptoms of yellowing or wilting. Stands harvested between April 1 – June 1 and sites prepared in the year of harvest and planted the following winter can have severe pales weevil problems.
- Protect the terminal bud (the bud located at the end of a limb marking the end of that year’s growth) from tip moth larvae. The best time for treatment is at planting. Seedlings planted and treated after February 1 may not have adequate time to absorb enough chemical to protect against the first cycle of tip moth larvae.
- Have the soil tested for phosphorous (P) by a local lab and follow their recommendations for fertilization at the time of planting.
- If you have coarse, sandy soil or if scalping is applied during or before planting, nitrogen fertilization may be required. Dormant season foliage analysis can help diagnose when nitrogen fertilization may be needed.
- Don’t let your seedlings get trampled by domestic animals such as cattle. It’s best to exclude domestic animals from your newly planted forest for the first two years. If you allow domestic animals in your new forest, try to keep all feed troughs and mineral supplement areas outside the newly planted area.
- Monitor seedlings throughout the summer for issues that may arise and notify your ArborGen Reforestation Advisor immediately if you see unhealthy seedlings.
Fewer Trees-Per-Acre with Higher Genetics
Dr. Paul Jeffreys discusses important planting density considerations for your next planting.
Paul Jeffreys, Ph.D.
Western Tennessee, Alabama, and Mississippi
Geoffrey Lee Hill
Georgia, Virginia, Eastern Tennessee, Northern North Carolina
Eastern Texas, Southern Louisiana
Senior Business Specialist, Texas
Southern North Carolina, South Carolina
Florida Gulf Coast, South Alabama, Southwest Georgia
Arkansas, Northern Louisiana, and Oklahoma
Manager, Reforestation Advisors