Integrated Pest Management in Southern Pine Forests

R.C. Thatcher - Program Manager, Integrated Pest Management RD&A Program for Bark Beetles of Southern Pines, Pineville, LA.,
G.N. Mason - Project Leader, Silvicultural Options for Gypsy Moth, Northeastern Forest Experiment Station, Morgantown, WV, and
G.D. Hertel - Program Manager for Gypsy Moth Research, Northeastern Forest Experiment Station, Broomall, PA.
Mason and Hertel were Research Coordinator and Applications Coordinator for the IPM Program when this work was conducted.

Integrated Pest Management Handbook, USDA, Forest Service, Agriculture Handbook 650, April 1986.

In 1980, the Forest Service and the Cooperative State Research Service of the U.S. Department of Agriculture initiated the Integrated Pest Management Research, Development, and Applications Program for Bark Beetles of Southern Pines. This research/applications effort concentrates on pine bark beetles and associated tree diseases in the South. This is one in a series of Integrated Pest Management handbooks.

Technologies Needed for Better Management Decisionmaking

Conscientious forest manager or landowners will want to assess pest potentials and take preventive or remedial management actions when and if they will benefit their operations. They need answers to such questions as: Will pests occur? Which one(s)? Where and when will infestations occur? How much damage can be expected? What is the best management practice to prevent or minimize the losses? Several technologies have been developed to aid in answering these questions and for use in making decisions concerned with the detection, evaluation, prevention, or reduction of losses due to insects and tree-killing diseases affecting southern pines. These technologies may be roughly categorized into five groups: 1) Methods for measuring and predicting the biological and economic impacts of pests; 2) methods for determining the utilization potential and suitability or profitability of harvesting and processing beetle-killed timber for various wood products; 3) methods for measuring and predicting population change; 4) methods to measure site, tree, and stand conditions affecting host susceptibility and suitability for pests; and 5) methods for making control decisions and applying control strategies.

Impacts
Incorporation of pest management techniques into forest management plans requires a capability to evaluate and predict immediate and long-range effects of destructive organisms. The capability depends on being able to accurately measure and predict pest impacts and understanding their interrelationship with other biological, environmental, and economic factors. Table 5 gives descriptions of techniques available for several major pests and sources of information about these techniques.

Table 5 – Techniques to measure and predict pest impacts

Subject pest	Available technology	Description	Reference
Southern pine beetle		Procedure for determining point-in-time and annual timber mortality caused by bark beetles for large areas of mixed ownership	Ward and others 1985
	SPB COMP	Technique for projecting changes in SPB infestation areal coverage for multistate areas (subregions) based on climatic events	Michaels 1984   Michaels and others   1985
	ITEMS/ SPB MICRO- BEETLES	Simulation models for projecting the effects of and economic returns from various management practices in single or multiple stands in the presence or absence of SPB over a rotation	Vasievich and   Thompson 1985   Thompson 1985
	CLEMBEETLE	Simulation model for determining the probability of SPB infestation occurrence and expected loss in single or multiple stands under various management regimes in the next year up to a rotation	Hedden 1985a, 1985b
	TAMBEETLE/ TFS SPOT GROWTH ARKANSAS SPB	Spot growth models for predicting timber mortality and economic losses caused by SPB over the next 30-90 days	Feldman and others   1985   Saunders 1985   Billings 1985a   Stephen 1985   Stephen and Lih 1985
Annosus root rot	GY-ANNOSUS	Model for predicting cubic foot yields for thinned loblolly pine plantations with and without annosus root rot infection	Hokans and Alexander   1985   Hokans and others 1985
	Annosus sampling	Nondestructive sampling techniques for determining annosus root rot infection level in thinned loblolly pine plantations	Alexander 1985   Alexander and others   1985
Fusiform rust	FUSIFORM RUST YIELD- SLASH/ LOBLOLLY	Model for predicting yields for unthinned slash and loblolly pine plantations infected with fusiform rust	Nance and others 1985   Nance and Shoulders   1985

Technology is now available to monitor SPB impacts through aerial sampling and to estimate current and annual timber mortality over multicounty or management-unit size areas (Ward and others 1985). Trends in beetle activity at a multicounty (in other words, climatic district) level can also be projected from year to year based on current spot detection records, timber resources, and climatic information (Michaels 1984). The approach utilizes climatic information from multicounty districts, data from infestation predictors (or indicator) counties, and early season population estimates to forecast beetle outbreak trends in the coming season. The economic consequences of management actions on southern pine forests, with or without beetle infestations,

Figure 2 – Subregions in Southern States used to project changes in areal coverage of southern pine beetle infestation.

can be evaluated using one of several beetle, stand, and economic simulators (ITEMS, SPB-MICROBEETLES, CLEMBEETLE) (Hedden 1985a, b; Thompson 1985; Vasievich and Thompson 1985). In-puts of stand conditions, management objectives or cultural treatments, economic and time constraints, and SPB infestation frequency lead to user-specific reports on forest conditions and the cost/benefits of management options. Control actions can then be tailored to individual management situations.

SPB spot growth, tree mortality, and economic losses can be accurately predicted over a 30- to 90-day period using the Texas Forest Service, Texas A&M University, or Arkansas spot growth models (Billings 1985a; Feldman and others 1985; Stephen and Lih 1985). These systems utilize pest population estimates, stand characteristics, weather, and economic data provided by the user. Plantation failures, growth and quality decline, and tree mortality losses from fusiform rust, annosus root rot, and littleleaf disease amount to hundreds of millions of dollars annually. Incidence and severity information is vital in making appropriate management decisions for specific

Figure 3 – Use of microcomputers to simulate changes in economic returns from stands as a result of treatment and presence or absence of SPB infestations.

stands. A yield prediction system (FUSIFORM RUST YIELD-SLASH/LOBLOLLY) has been developed for unthinned slash and loblolly pine plantations infected with fusiform rust (Nance and others 1985; Nance and Shoulders 1985). Loss projections through the end of the rotation can serve as a basis for management decisionmaking.

Figure 4a – Plantation severely infected with fusiform rust.

Figure 4b – Main stem infection by fusiform rust.

An annosus root rot sampling system is now available to determine the percentage of root infection in thinned loblolly pine plantations (Alexander 1985; Alexander and others 1985). These data are input to a growth and yield model (GY-ANNOSUS) that projects growth and volume losses resultling from annosus infection (Hokans and Alexander 1985; Hokans and others 1985). Using this tool, plantation managers can evaluate management options and the need for (and consequences of) these actions. Utilization A costly consequence of the SPB outbreak of the seventies was that about half the timber killed was never utilized. Millions of cubic feet of high-quality pine were left to rot in the woods. More of this valuable resource could have been used if timber buyers and mill operators had been aware of its suitability for various wood products and been willing to use it (Woodson 1985). Table 6 lists

Figure 5 – Removal of a cubic foot soil sample to determine percent root infection by annosus root rot.

Table 6 – Techniques to determine utilization potential

Subject pest	Available technology	Description	Reference
Southern pine beetle	Field appearance classes	A method to determine utilization potential of beetle-killed timber for various wood products based on field appearance	Levi 1981
	SAMTAM	Sawmill decision models for green, uninfested timber (SAMTAM I), and beetle-killed timber (SAMTAM II)	Patterson   1985, 1986

Utilization analysis models developed for green and beetle-killed timber allow sawmill managers to consider market values, operating costs, and mill efficiency information in estimating profit margins for lumber based on size and grade and for residues based on weight. This system, consisting of SAMTAM I (for green logs) and its submodel SAMTAM II (which considers reduced stumpage prices, reduced product yields, and greater residue product yields, and greater residue overrun in determining potential profit from beetle-killed timber with differing log sizes and stages for operational use (Patterson 1985, 1986).

Figure 6 – Utilization models for determining profitability of harvesting and processing green and bettle-killed sawtimber.

An earlier development (Levi 1981) is the correlation of the appearance of beetle-killed trees in the field to the wood products for which they are most suited (table 7). These same appearance classes have also been related to wood physical properties; this correlation allows for expansion of the results to any number of wood product uses.

Figure 7a – Class A beetle-killed tree with no needles but twigs still attached.

Figure 7b – Class B beetle-killed tree with no needles ans some twigs and branches lost.

Table 7 – Utilization guidelines for beetle-killed trees¹

Products	Class A	Class B	Comments
Lumber – appearance	Not recommended	Not recommended	Blue-stain prohibits use.
Lumber – dimension	Can be used with caution	Not recommended	Should be kilin dried to prevent emergence of secondary insects. Low moisture content may dull saws and chipper knives faster than with sound wood and may require milder kiln schedule. Do not use where toughness is important.
Lumber – decorative boards and paneling	Can be used	Can be used	Should be kiln dried.
Posts, poles, piling	Not recommended	Not recommended	Toughness and preservative treatability may be highly variable.
Plywood	Can be used	Not recommended	Adhesives and gluing practices may have to be adjusted.
Hardboard, particle-board, medium density fiberboard	Can be used	Can be used	Low moisture content may affect some production schedules. Should be mixed with sound wood.
Pulp	Can be used	Can be used	Blue-stain and low moisture content may affect pulping process and chemical or energy requirements. Should be mixed with sound wood, particularly where strength is important.
Fuelwood	Can be used	Can be used	Low moisture content increases heat value.

¹Source: Levi, M.P. A guide for using beetle-killed southern pine based on tree appearance. Agric. Handb. 572. Washington, DC: U.S. Department of Agriculture; 1981. 19 p.

Pest Population Change
Southern pine beetle outbreaks come and go, and their intensity varies geographically, seasonally, and from year to year. Interpreting and anticipating these changes in activity levels are fundamental to developing ways to reduce potential impacts. These processes require a thorough understanding of the SPB's relationship with associated insects, tree diseases, the host, and the environment.

Sampling techniques have been developed to estimate SPB and Ips spp. population numbers in individual trees and infestaions. These estimates are useful to researchers and to pest management specialists who need such information to plan aerial surveys and recommend management actions.

Figure 8 – Sampling SPB populations in standing tree.

Figure 9 – Sampling logging residue for Ips spp. in thinned stand.

Sampling techniques are also available to estimate Ips spp. population numbers in logging residue following thinning or clearcutting. This information will eventually be correlated with tree mortality in thinned stands and provide a basis for decisions concerning management actions.

Newly developed procedures are available to measure population change and determine the role that various biological and environmental factors play in regulating beetle numbers. These procedures should enable pest managers to predict population and tree mortality trends and evaluate the effectiveness of treatment strategies.

Associations of two or more bark beetle species in the same host tree are common. Under certain conditions, these associations favor attacks, brood development, and survival; under other conditions, intense competition and beetle mortality occur. Information on these beneficial and competitive interactions within and between bark beetle species and with other insects infesting the same host tree, along with information on life processes and developmental rates under different environmental conditions, has been incorporated into computerized population dynamics models that mimic field conditions Texas, Arkansas, and other States. These models can be used by Federal and State pest management specialists to predict SPB population trends and to evaluate the effectiveness of treatment in preventing or reducing pest-caused losses.

New information is available on the relationship between southern pine beetles and the fungi they carry that may help us understand fluctuations in beetle outbreaks. Results to date indicate that one fungus carried by adult female beetles favors beetle brood development and survival. The absence of another fungus causing blue staining of wood (Ceratocystis minor) in infested trees may signal conditions favorable for an outbreak. This knowledge may soon permit pest management specialists to accurately predict the development or decline of SPB outbreaks.

Table 8 lists the various techniques available to help interpret and anticipate changes in pest populations.

Table 8 – Techniques to measure and predict pest population change

Subject pest	Available technology	Description	Reference
SPB/Ips	SPB/Ips sampling	Procedures for sampling SPB and Ips spp. in standing trees, Ips spp. in logging residue	Coulson and others 1976 Foltz and others 1977, 1985
	TAMBEETLE/ ARKANSAS SPB	Life processes and population dynamics models for SPB and/or Ips spp.	Feldman and others 1985 Saunders 1985 Stephen and Lih 1985
	TFS SPOT GROWTH	A method to project SPB spot growth over the next 30 days	Billings 1985a

Host Susceptibility and Suitability
Susceptibility of host pines to beetle attack and their suitability for brood development and survival are important factors affecting bark beetle population growth or decline. These factors can be used in predicting outbreak and tree mortality trends and in developing strategies to prevent or reduce losses. The roles of host and stand conditions, stand disturbance, and tree disease, alone and in combination, are being evaluated and methods developed for using this information in predicting beetle outbreaks (table 9).

Table 9 – Techniques for rating host susceptibility and suitability

Subject pest	Available technology	Description	Reference
Southern pine beetle	TFS GRID HAZARD	Rating of 18,000-acre grid blocks for relative susceptibility to SPB attack	Billings 1985c; Billings and others 1985
	Texas SPB hazard- rating guide	Rating of stand susceptibility to SPB attack in Texas and Louisiana	Mason and others 1985
	ARKANSAS SPB	Rating of individual pine stand susceptibility to SPB attack in Arkansas	Stephen 1985 Stephen and Lih 1985
	MS HAZARD B	Rating of individual pine stand susceptibility to SPB attack in Mississippi and Alabama	Nebecker 1985
	PIEDMONT RISK	Rating of individual pine stand susceptibility to SPB attack in the Piedmont	Hedden 1985c
	MOUNTAIN RISK	Rating of individual pine stand susceptibility to SPB attack in the mountains of North Carolina, Virginia, and Georgia	Hedden 1985d
	Tree vigor index	A method of rating an individual tree's susceptibility to SPB attack	Hain and others 1985 Hodges and others 1985
Fusiform rust	Hazard rating	Rating pine stand susceptibility to fusiform rust infection	Anderson and Mistretta 1982
	Tree vigor index	A method of rating an individual tree's risk of dying from fusiform rust infection	Miller and others 1985
Annosus root rot	Hazard rating	Rating of pine stand susceptibility to annosus root rot and determination of percent infection	Alexander 1985 Alexander and others 1985 Anderson and Mistretta 1982
Littleleaf disease	Hazard rating	Rating of pine stand susceptibility to littleleaf disease loss	Anderson and Mistretta 1982 Oak 1985

Attempts to identify susceptible or resistant trees have included measurements of physical and chemical characteristics of host trees before and after they were stresses by natural and human-caused disturbance. Studies of the reaction of pine inoculated with one of the fungi associated with SPB have suggested that the size and severity of the host reaction may be indicative of tree vigor. Similarly, the effects of varying degrees of root and basal stem wounding on host condition and subsequent pest attack have been evaluated. Results from individual trees, trees in the same stand, and trees in different stands have been correlated with beetle attack and development, spot growth patterns, and ultimately, tree mortality. SPB attack thresholds have been determined and date from these studies used to develop a tree vigor index for ranking host susceptibility to SPB attack. Findings have, in turn, been integrated into population dynamics models and will eventually be used to predict the risk potential for entire stands.	Figure 10 – Measuring stand conditions associated with pest outbreaks.
Figure 11 – Determining resin characteristics prior to SPB attack.	Figure 12 – Determining soil compaction following thinning.
Figure 13 – Use of tree tents to determine the number of beetles required to overcome pines in various "vigor classes".	Figure 14 – Hazard rating of 18,000-acre grid blocks in east Texas based on site and stand conditions and associated SPB infestation history.
Stand hazard rating can be a valuable tool in locating potential high-risk areas for SPB, annosus root rot, and/or littleleaf disease and evaluating the need for special surveillance and management actions (Anderson and Hoffard 1985; Mason 1980; Mason and others 1985; Tainter and Oak 1985). Hazard ratings serve as an early warning system be describing site and stand characteristics most often associated with infestation occurrence and severity. The likelihood of infestation depends on the presence of susceptible trees and stands and beetle and/or disease activity in the same area. An approach has been developed for integrating bark beetle or disease population estimates with stand hazard to determine the probability of an individual stand being attacked (Hedden 1985a, b). Hazard-rating systems for SPB, annosus root rot, and littleleaf disease have been applied to Federal, State, industrial, and small, private, nonindustrial holdings in several States (Hertel and others 1985). Historic and current bark beetle infestations have been correlated with hazard-rated stands with	Figure 15 – Top map shows distribution of high-hazard littleleaf disease sites in Piedmont region of the Southeast. Bottom map shows distribution of southern pine beetle high-hazard stands in Piedmont region of the Southeast.

Control
Losses caused by many forest pests can be effectively minimized through management practices that promote tree and stand vigor under different site and stand conditions. Guidelines have been developed for managing these stands in the pine regions of the Piedmont (Belanger and Malac 1980; Belanger and others 1986) and in the Coastal Plain (Nebeker and Hodges 1985). In other situations, direct control methods are required as a temporary expedient or because other management actions would be ineffective in dealing with extensive areas of susceptible host type and a high level of beetle activity. When outbreaks do occur, early detection is necessary, control priorities must be set, and the most effective methods must be employed to minimize economic losses (Swain and Remion 1981). Techniques available to aid in determining control strategies are listed in table 10.

Table 10 – Techniques for making control decisions

Subject pest	Available technology	Description	Reference
Fusiform rust		Guidelines for salvage cutting fusiform rust-infected slash and loblolly pine plantations	Anderson and Mistretta 1982 Belanger and others 1985
Pine bark beetles		Effects of different thinning practices on subsequent pest activity	Nebeker and others 1985
		Guidelines for thinning plantations under wet and dry soil conditions	Nebeker and Hodges 1985
		Trapping procedure for determining time of peak BTB and Ips spp. flight and need for control	Fatzinger 1985a, 1985b
Southern pine beetle	CLEMBEETLE	Simulation model for determining probability of SPB infestation occurrence and expected loss in single or multiple stands under various management regimes in the next year up to a rotation	Hedden 1985a, 1985b
	ITEMS/SPB MICRO-BEETLE	Simulation models for projecting the effects of and economic returns from various management practices in single or multiple stands in the presence or absence of SPB over a rotation	Thompson 1985 Vasievich and Thompson 1985
		Use of microencapsulated attractant to suppress SPB spot growth (pending EPA registration)	Payne and others 1985
		Insecticides for preventive and/or remedial control of SPB, Ips spp., and/or BTB	USDA 1984a Hastings and Coster 1981 Nord and others 1985 Taylor 1984
	TAMBEETLE/ ARKANSAS SPB/TFS SPOT GROWTH	Spot growth models for predicting timber predicting timber mortality and economic losses caused by SPB over next 30-90 days as an aid to control decisionmaking	Feldman and others 1985 Stephen and Lih 1985 Billings 1985a
		Cultural techniques for reducing SPB-caused losses	Belanger and Malac 1980
		Direct control methods for SPB	Swain and Remion 1981
		Salvage removal	USDA 1981b Texas Forest Service 1985b Ham 1983a
		Cut-and-leave	USDA 1981a Texas Forest Service 1985a Ham 1983b
		Pile-and-burn	USDA 1984b
	IPM decision key	Information management system to aid in decision making for several insect and disease problems	Anderson and others 1984
	SPB decision support system	Decision support system to aid in SPB control decision making	Turnbow and others 1983

Fusiform rust salvage cutting operations undertaken in industrial plantations in South Carolina, Georgia, Florida, and Alabama have been removed a high percentage of severely infected slash and loblolly pines that would otherwise have died before final harvest. This cutting has left a significantly larger proportion of healthy trees in the residual stands (Belanger and others 1985; Miller and others 1985). Preliminary guidelines for thinning and sanitation salvaging of such plantations have been developed for use in managing similarly infected areas.

Research indicated that, when properly deployed, a microencapsulated slow-release formulation of the SPB attractant frontalure can successfully stop SPB spot growth. This has been demonstrated in Georgia and Texas (Payne and others 1985). This substance, once it has been registered by the U.S. Environmental Protection Agency (EPA), may serve as an alternative treatment technique, especially in high-value or special-use areas. Guidelines for the proper use and evaluation of the attractant tactic are being developed for Federal and State pest management specialists.

Figure 16 – Deployment strategy for using frontalure to disrupt SPB spot growth. Black indicates post-brood and non-host trees; orange indicates older brood trees; yellow indicates recently attacked trees; and green, uninfested trees.

Figure 17 – Use of turpentine-baited traps to monitor black turpentine beetle peak flight in a high-value stand.

A technique for monitoring black turpentine beetle flight by placing turpentine-baited traps in naval stores stands is available (Fatzinger 1985a, b).

These traps also capture other insects, including Ips engraver beetles, woodborers, and reproduction weevils. Such traps have been used to aid managers of naval stores in determining periods of peak bark beetle flight and properly timing control measures.

In the area of chemical control, chloropyrifos (Dursban®) and fenitrothion (Sumithion®) have proven effective against SPB, and have been registered for protecting green pines from bark beetle attack and controlling existing SPB infestations inindividual trees (USDA 1984a; Hastings and Coster1981; Taylor 1984). However, the availability of Sumithion® for sale in the United States is currently limited.

Figure 18 – Standing tree chemical treatment to protect green pines from bark beetle attack.

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