Tip Moth Research Articles

Loblolly Pine Susceptibility to Nantucket Pine Tip Moth: Do Tree Genetics Play a Role?

Abstract The Nantucket pine tip moth (NPTM) (Rhyacionia frustrana Comstock) is a regeneration pest of young loblolly pines (Pinus taeda L.) that causes tree deformity, shoot dieback, and growth declines. Different silvicultural techniques are used to grow loblolly pine more effectively, including improved genotypes. Some scientists and growers have hypothesized that more expensive full-sibling families (control-pollinated [CP]) seedlings may be more susceptible to NPTM than open-pollinated (OP) families. The study objective was to assess the susceptibility to NPTM of seven loblolly OP and CP families commonly planted in the southeastern United States by observing NPTM infestation rates and pine growth metrics (height, groundline diameter, volume index, and stem form) over two growing seasons. The NPTM infestation rates varied throughout both growing seasons; however, there was no difference in infestation rates among any of the families. Pine growth metrics varied among families at the time of planting; however, growth metrics did not vary after the first and second growing seasons. Results of this study suggest that NPTM management tactics, such as insecticide use, should not be prioritized based on loblolly pine families alone, as the CP families assessed in this study were not more susceptible to NPTM than OP families.

Efficacy of four systemic insecticides for reducing Nantucket pine tip moth (Rhyaciona frustrana) (Lepidoptera: Tortricidae) infestation levels and improving growth metrics in loblolly pines.

The Nantucket pine tip moth (NPTM) (Rhyacionia frustrana Comstock) is a native, regeneration pest of young loblolly pines (Pinus taeda L.), causing shoot dieback, tree deformity, and growth and volume declines. Soil applications of systemic insecticides may be an effective strategy to suppress NPTM populations. The study objective was to assess the efficacy of four systemic insecticide treatments (chlorantraniliprole, dinotefuran, fipronil, and imidacloprid) for two growing seasons in outplanted bareroot and containerized seedling trials. Response variables included NPTM infestation rates, along with tree height, groundline diameter, volume index, and stem form. Infestation rates significantly decreased for each systemic insecticide treatment during the first year compared to controls, although dinotefuran and imidacloprid provided season-long control in one trial. Chlorantraniliprole reduced NPTM infestation rates for two growing seasons in both trials. While imidacloprid treatments did not alter growth metrics except for one comparison, fipronil and dinotefuran treatments improved several growth metrics. Chlorantraniliprole consistently improved growth metrics throughout the study.

Management Implications for the Nantucket Pine Tip Moth From Temperature-Induced Shifts in Phenology and Voltinism Attributed to Climate Change.

Forest insect pest phenology and infestation pressure may shift as temperatures continue to warm due to climate change, resulting in greater challenges for sustainable forest management . The Nantucket pine tip moth (NPTM) (Rhyacionia frustrana Comstock) (Lepidoptera: Tortricidae) is a native forest regeneration pest in the southeastern U.S. with multiple generations per year. Changes in NPTM voltinism may result from temperature-induced shifts in NPTM phenology. Degree-day models have been used to develop optimal spray dates (OSDs) for NPTM. The 2000 Spray Timing Model (STM), based on temperature data from 1960 to 2000, provided generation-specific 5-d OSDs to effectively time applications of contact insecticides. An updated degree-day model, the 2019 STM, is based on temperature data from 2000 to 2019 and was used to detect changes in voltinism as well as shifts in phenology and OSDs. Based on the model, increased voltinism occurred at 6 of the 28 study locations (21%). Changes in voltinism occurred in the Piedmont and Coastal Plain of Georgia, U.S., with shifts from three to four or four to five generations a year, depending on location. The OSDs from the 2019 STM were compared to the 2000 STM OSDs. Over half (57%) of the OSDs differed by 5-15 d, with the majority (66%) resulting in earlier spray dates. The 2019 STM will help growers adapt NPTM control tactics to temperature-induced phenology shifts. NPTM serves as an example of temperature-induced changes attributed to climate change in a forest insect pest with important implications to forest management.

Assessing imidacloprid for Nantucket pine tip moth (Rhyacionia frustrana) suppression through regional collaborative research and focus group evaluation

Nantucket pine tip moth (NPTM) [Rhyacionia frustrana (Lepidoptera: Tortricidae)] is a pest of young pine trees. The goal of this research project was two-fold: 1) to evaluate imidacloprid for NPTM suppression in South Georgia and 2) to incorporate county agents into a research project to facilitate knowledge transfer and extension training. Research sites in one-year planted loblolly pine stands were established by an extension specialist and county agents in five counties in South Georgia. Loblolly pines were assigned one of three treatments: untreated control, soil drench, and foliar spray. Trees were treated at a rate that would treat 500 trees per acre. Pines were assessed for NPTM infestation five times during the year, set to coincide with each NPTM generation. Tree height was measured at the end of the growing season. Qualitative data was collected on the agents' experience during a Zoom focus group and with emailed questionnaires.Imidacloprid drench and spray treatments resulted in lower NPTM infestation rates compared to untreated controls. However, while infestations rates were significantly lower, benefits were not conveyed to increased tree height. Imidacloprid treated trees were no taller than control trees.Collaborating with county agents enhanced this research project and benefitted both agents and the extension specialist. County agent involvement enhanced their job performance, allowed them to positively influence county stakeholders, contributed to core job competencies, and increased knowledge in forest health. Incorporating extension with research throughout the course of this study has been beneficial for both research outcomes and knowledge transfer.

Efficacy of Insecticides for Reducing Maple Tip Moth Damage on Red Maple, 2021

Efficacy of Insecticides for Reducing Maple Tip Moth Damage on Red Maple, 2021

Outbreak and life cycle of the hook tip moth, Deroca inconclusa (Walker,1856) (Lepidoptera: Drepanidae) on Himalayan Dogwood, Cornus capitata Wall. ex Roxb. (Cornaceae) in Garhwal region of Western Himalaya, India

During the course of survey carried out in Chakrata hills (Chakrata Forest Division, Dehradun district, Uttarakhand (Western Himalaya), sporadic infestation by the hook tip moth, Deroca inconclusa (Walker,1856) (Lepidoptera: Drepanidae : Drepaninae) was recorded on Cornus capitata Wall. ex Roxb. trees in Chakrata Reserve Forest at several locations. Outbreak of the hook tip moth is being reported for the first time from this region along with its life history on C. capitata from the Garhwal region of the Western Himalaya.

Limited Scope Risk Assessment for Nontarget Ground-Dwelling Arthropods From Systemic Insecticide Applications to Young Pines.

The Nantucket pine tip moth (NPTM) [Rhyacionia frustrana (Comstock)], a native regeneration pest on young loblolly pines (Pinus taeda L.), negatively impacts pine growth. An emerging management approach is to apply systemic insecticides to seedlings to reduce NPTM damage. These systemic insecticide applications generally occur once, perhaps twice, during the first few years of loblolly pine growth. However, these applications could lead to unintended environmental consequences to nontarget organisms. The purpose of this study was to assess potential nontarget effects from four systemic insecticide applications by assessing ground-dwelling arthropod trap catch, with a focus on collembolan trap catch and genera richness. Loblolly seedlings (24 seedlings per plot) at three sites in southeast Georgia were treated with either chlorantraniliprole, dinotefuran, fipronil, or imidacloprid or left untreated as a control. Arthropods were collected with pitfall traps that were deployed for 5 d in July, August, and September 2019, 7-9 mo after treatment. Ground-dwelling arthropod trap catch, arthropod order trap catch, collembolan trap catch, and collembolan genera richness did not vary among insecticide treatments and the untreated control in this mid-term insecticide risk assessment. While no significant effects of insecticide treatment were observed, ground-dwelling arthropod trap catch, collembolan trap catch, and collembolan genera richness differed among collection times. This study was the first of its kind in a young pine stand setting and is an important first step to understanding risk in these settings. Information on nontarget risks of management practices informs growers of the level of environmental risk associated with systemic insecticides.

Key Plant, Key Pests: Pine Species (Pinus sp.)

This series of Key Plant, Key Pests publications are designed for Florida gardeners, horticulturalists and landscape professionals to help identify common pests associated with common Florida flora. This publication, the seventh in the Key Plant, Key Pests series, helps identify the most common pests found on Pinus sp.
 This publication provides information and general management recommendations for borers, pine sawflies, pine bark beetles, pine tip moths, fusarium rust, pine chlorosis, and pitch canker.

Crown physiological responses of loblolly pine clones and families to silvicultural intensity: Assessing the effect of crown ideotype

Clonal forestry must be linked with intensive silvicultural practices to increase forest productivity of loblolly pine (Pinus taeda L.) in the southern United States. Although the positive growth responses due to intensive silviculture have been reported extensively, much less is known about the physiological processes that drive these responses. This study assessed the responses of growth, leaf area, leaf-level gas exchange and foliage morphology of 4year-old loblolly pine clones and families to changes in silvicultural intensity on the Virginia Piedmont (VA) and North Carolina Coastal Plain (NC). Four clones (differing in crown ideotype), 1 control-mass-pollinated (CMP) and 1 open-pollinated (OP) family were evaluated in two levels of silviculture (operational and intensive). The operational silvicultural treatment included only banded weed control, whereas the operational silvicultural treatment included broadcast weed control, fertilization and tip moth control. The effect of genotype and silvicultural intensity were site-specific, and expressed mostly at VA. The intensive silvicultural treatment increased stem volume by 68% and 36% relative to the operational silvicultural treatment at VA and NC, respectively. At VA, the differences in the leaf area responses to the silvicultural treatment among genotypes differed between 60 and 146%, which suggested great differences in growth efficiency among the genotypes. These responses were not linked to changes in leaf physiology and morphology. The seasonal variation of gas exchange parameters was similar between sites, but significant differences in leaf physiology and morphology were found among the genotypes. However, this variation was neither attributed to the genetic source (clonal versus non-clonal) nor the crown ideotype (broad- versus narrow-crown) as hypothesized. Understanding the differences in the crown physiological processes among loblolly pine genotypes may be required to optimize the gains expected from clonal forestry.

Systemic Control of Nantucket Pine Tip Moth (Rhyacionia frustrana Scudder in Comstock, 1880) Enhances Seedling Vigor, Plantation Establishment, and Early Stand-Level Productivity in Pinus taeda L.

Establishment is a vulnerable and expensive stage of stand development in intensively managed pine plantations. We evaluated the capacity of establishing loblolly pine (Pinus taeda L.) plantations to increase productivity by systemic control of Nantucket pine tip moth (Rhyacionia frustrana Scudder in Comstock, 1880). In January 2009, four genotypes of improved genetics loblolly pine were planted in whole-plot treatments of herbaceous competition control at an upper coastal plain (UCP) site and phosphorus fertilization at a lower coastal plain (LCP) site, and split-plot treatments of tip moth control. Trees were monitored for tip moth infestation levels, vigor, survival, and stand-level biomass production for 2 years. During this time, tip moth infestation levels were very high at both sites, averaging 69% at UCP and 70% at LCP. However, levels averaged only 8% at UCP and 39% at LCP in treatments that included applications of systemic insecticides at planting. At LCP, biomass production averaged 2,159 kg ha 1 after 2 years. Protection from tip moth increased LCP biomass by 11% averaged across genotypes and 20 –30% for the most responsive genotypes. At UCP, 2-year pine biomass production was much lower at 114.5 kg ha 1 and was increased 150% by protection from tip moth. At UCP, there was a strong effect of genetics whereby one genotype experienced very high mortality (mean of 30%) attributed to meteorological conditions of the establishment year; however, this was greatly decreased (17%) by protection from the interacting stress of tip moth damage. We conclude that systemic control of tip moth using imidacloprid soil tablets has the potential to greatly enhance pine plantation establishment success and early productivity in areas of heavy pest pressure, which may compound through stand development.

De novo Assembly and Characterization of the Global Transcriptome for Rhyacionia leptotubula Using Illumina Paired-End Sequencing

BackgroundThe pine tip moth, Rhyacionia leptotubula (Lepidoptera: Tortricidae) is one of the most destructive forestry pests in Yunnan Province, China. Despite its importance, less is known regarding all aspects of this pest. Understanding the genetic information of it is essential for exploring the specific traits at the molecular level. Thus, we here sequenced the transcriptome of R. leptotubula with high-throughput Illumina sequencing.Methodology/Principal FindingsIn a single run, more than 60 million sequencing reads were generated. De novo assembling was performed to generate a collection of 46,910 unigenes with mean length of 642 bp. Based on Blastx search with an E-value cut-off of 10−5, 22,581 unigenes showed significant similarities to known proteins from National Center for Biotechnology Information (NCBI) non-redundant (Nr) protein database. Of these annotated unigenes, 10,360, 6,937 and 13,894 were assigned to Gene Ontology (GO), Clusters of Orthologous Group (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, respectively. A total of 5,926 unigenes were annotated with domain similarity derived functional information, of which 55 and 39 unigenes respectively encoding the insecticide resistance related enzymes, cytochrome P450 and carboxylesterase. Using the transcriptome data, 47 unigenes belonging to the typical “stress” genes of heat shock protein (Hsp) family were retrieved. Furthermore, 1,450 simple sequence repeats (SSRs) were detected; 3.09% of the unigenes contained SSRs. Large numbers of SSR primer pairs were designed and out of randomly verified primer pairs 80% were successfully yielded amplicons.Conclusions/SignificanceA large of putative R. leptotubula transcript sequences has been obtained from the deep sequencing, which extensively increases the comprehensive and integrated genomic resources of this pest. This large-scale transcriptome dataset will be an important information platform for promoting our investigation of the molecular mechanisms from various aspects in this species.

Long-Term Effects of Pine Tip Moth (Lepidoptera: Tortricidae) Control, Vegetation Control, and Fertilization on Growth and Yield of Loblolly Pine, Pinus taeda L.

Studies were conducted in Georgia and North Carolina to determine the long-term growth impact of pine tip moth, Rhyacionia spp., attacks on loblolly pines which had been treated with different combinations of insecticides for tip moth control, herbicides for control of competing vegetation, and fertilizer. Height, diameter, and volume responses were significantly greater for tip moth and weed control at age 5, both in Georgia and North Carolina. There was no evidence of a positive response to fertilizer. The largest responses were due to tip moth control, which was the only treatment that retained a significant response through the termination of the study at age 15 in Georgia and age 20 in North Carolina. Stand volumes continued to increase on the tip moth control plots throughout the study with average gains of 3.1 m3/ha/yr (43.8 ft3/acre/yr) at the Georgia site at age 15 and 3.2 m3/ha/yr (45.8 ft3/acre/yr) at age 20 at the North Carolina site. Trees receiving tip moth control also had significantly better form than untreated trees when evaluated at age 5, which may be reflected in higher quality and more valuable forest products at harvest. Treatment responses observed in this study clearly show that tip moth control can provide benefits equal to or greater than other commonly used cultural treatments, and may be necessary to realize anticipated gains from intensive management of loblolly pine plantations when tip moth damage is heavy.

Morphological and genetic variation of the pine shoot tunnel beetle Placusa pinearum (Staphylinidae) in China

Placusa pinearum, a newly described beetle species found living in pine shoot tunnels bored by the pine tip moth, Dioryctria rubella (Pyralidae), has potential as a vector to transport biological agents for controlling this moth pest of pine trees because of the high degree of niche overlap (co-occurrence) between them. In order to help determine the suitability of potential biological control vectors, it is useful to obtain knowledge concerning the intraspecific variation of the vector. We examined P. pinearum collected from 14 different geographical populations in China using morphological and molecular markers. An UPGMA dendrogram based on morphological characters showed divergence of populations of P. pinearum in a comparison of beetles from southwestern and 3 other geographic regions (central, northwestern, and eastern regions). We also compared 965-nucleotide sequences of the mitochondrial cytochrome oxidase subunit I gene from 56 individuals; 19 haplotypes were identified based on 28 polymorphic sites in this region. A Bayesian phylogenetic tree showed significant genetic divergence among the different populations in eastern China. In addition, absence of shared haplotypes, coupled with high pairwise FST values, demonstrated significant genetic divergence between the populations from the southwest and the other 4 main geographical regions (eastern, southern, central, and northwestern regions). Generally, we found the morphological divergence to be congruent with genetic divergence in these P. pinearum populations. This information should be useful for selection of suitable source materials in the species gene pool for future biological control programs.

Mitochondrial genome of the pine tip moth Rhyacionia leptotubula (Lepidoptera: Tortricidae)

The complete nucleotide sequence of the mitochondrial genome of the pine tip moth Rhyacionia leptotubula (Lepidoptera, Tortricidae) was determined. The entire genome is 15,877 bp in length, encoding the standard set of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and an A+T-rich control region. The gene order is typical of Lepidoptera and differs from the insect ancestral type in the location of trnM. All protein-coding sequences start with a typical ATN codon, with the exception of COI, which begins with CGA. All tRNA genes could be folded into the typical cloverleaf secondary structure, except trnS2 lacking of dihydrouridine arm. Additionally, the 7-bp long ATACTAA motif is present in the intergenic space sequence located between trnS1 and nad1, and a long T-stretch with conserved ATAGA motif exists in the A+T-rich region, as found in Lepidoptera. The mitogenome given here provides important molecular information to phylogenetic and population genetic researches.

Use of Systemic Fipronil and Imidacloprid to Control Regeneration Pests of Loblolly Pine

Regeneration pests of loblolly pine (Pinus taeda L.) threaten growth and survival in intensively managed loblolly pine plantations throughout the southeastern United States. The Nantucket pine tip moth, Rhyacionia frustrana (Comstock), in particular, often reduces growth of loblolly pine but has been difficult to control with traditional insecticides due to multiple annual generations and multi-year infestations which are difficult to predict in timing and location. Relatively new systemic insecticide products offer a solution in that their efficacy persists through multiple generations and years after a single application. Efficacy of systemic imidacloprid and fipronil were evaluated side by side across multiple sites in Virginia. Significant reductions in Nantucket pine tip moth damage were noted in trees treated with either the imidacloprid or fipronil product compared with check trees. After 2 yr, growth improvement of treated trees relative to controls was modest and not significant at all sites, but per acre volume indices were significantly greater in treated blocks as a result of higher tree survival. Reduced seedling mortality was attributed primarily to prevention of damage by pales weevil, Hylobius pales Herbst (Coleoptera: Curculionidae), by both insecticide treatments. Control of pales weevil in addition to pine tip moth suggests that systemic insecticide products with a long window of efficacy might control additional nontargeted pests.

Growth responses to planting density and management intensity in loblolly pine plantations in the southeastern USA Lower Coastal Plain

• Background A culture/density study was established in 1995 in the Lower Coastal Plain of the southeastern USA to evaluate the effects of intensive silviculture and current operational practices on the growth and yield of loblolly pine plantations across a wide range of planting densities (741–4,448 trees/ha). The operational regime consisted of bedding and herbicide application in site preparation and fertilizer applications at planting and in the eighth and 12th growing seasons. The intensive management regime had additional complete competition control, tip moths control, and more repeated fertilization treatments.

Phenotypic analysis of first-year traits in a pseudo-backcross {(slash x loblolly) x slash} and the open-pollinated families of the pure-species progenitors

A single test, including one pseudo-backcross (Pinus elliottii x Pinus taeda) x P. elliottii and open-pollinated families of the pure species progenitors, was established in North Central Florida in December 2007 to study the transfer of the fast-growing characteristics from a P. taeda L. (loblolly pine) parent into the P. elliottii Engelm. (slash pine) background. Several traits were measured in the first growing season: height growth, phenology, tip moth incidence, stem traits, crown architectural and needle traits. Heterosis was evaluated for each trait using analyses of variance by fitting a linear mixed model. All traits were significantly (p value < 0.05) different among families while the significance for heterosis varied by trait. Positive heterosis was found for average rate of shoot elongation (ASRE), total growth (TG), total height and number of needles per fascicle while the opposite was true for base diameter, top diameter, fascicle length, fascicle diameter, crown projected area and phenological traits (cessation, duration and day to reach 50% of the height). Average performance (i.e., no heterosis) was found for initiation of growth, number of branches, number of nodes, tip moth incidence, sheath length and specific leaf area. The analyses indicated that introgression of loblolly pine alleles into slash pine was effective and novel trait combinations were achieved. The pseudo-backcross had larger variation in early height growth than the slash pine families and was taller than all open-pollinated families at the end of the first season. Tip moth incidence was much lower than the loblolly pine family.

History, Distribution, Damage, and Life Cycle of a Pine Shoot Gall Sawfly, Xyela gallicaulis (Hymenoptera: Xyelidae)

Larvae of Xyela gallicaulis Smith cause shoot stem galls in young pines. Loblolly pine, Pinus taeda L., is the most seriously damaged, but galls have been observed on slash pine, P. elliottii var. elliottii Engelm., and shortleaf pine, P. echinata Mill. Studies in Virginia and Georgia confirm a 2-year life cycle. Larval development takes 4 - 6 wks. After feeding, larvae bore out of the galls and drop to the ground where they form a papery cocoon in the soil to pupate, and where they remain for 22 - 25 months. Adults emerge from cells constructed in the soil from early-December to mid-January of the second year. Eggs are inserted into the vegetative buds during odd-numbered years. Insect associates found feeding in or on gall tissues are the Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Tortricidae), and the weevil Conotrachelus carolinensis Schoof (Curculionidae).

Operational Considerations for Augmentation of &lt;I&gt;Trichogramma exiguum&lt;/I&gt; (Hymenoptera: Trichogrammatidae) for Suppression of &lt;I&gt;Rhyacionia frustrana&lt;/I&gt; (Lepidoptera: Tortricidae) in &lt;I&gt;Pinus taeda&lt;/I&gt; Plantations

Studies were performed to assess the operational feasibility of Trichogramma exiguum Pinto & Platner (Hymenoptera: Trichogrammatidae) augmentation for suppression of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lepidoptera: Tortricidae), in commercial loblolly pine, Pinus taeda L., plantations. Single inundative releases containing two cohorts of encapsulated T. exiguum at a potential rate of 224,200 +/- 27,600 females per ha per cohort were made into two 4-ha plots during the second R. frustrana generation in 2000. Augmentation failed to increase parasitism rates above those occurring naturally; yet, 10% fewer shoots were attacked by R. frustrana, but not below acceptable levels. Quality control data suggest that low emergence levels and intense predation by ants upon developing T. exiguum lowered actual release rates to 13,000 +/- 900 females per ha per cohort. The effect of capsule distribution and microclimate on the discovery of capsules by predators (indicated by some E. kuehniella egg removal), parasitoid predation (percentage of eggs removed or destroyed), and subsequent parasitoid emergence was investigated. Uniformly distributed capsules experienced significantly higher predation levels than clustered capsules, and capsules exposed to field conditions for 5 d experienced higher predation than those exposed for 3 d, independently of distribution. Discovery of capsules by predators was unaffected by distribution or exposure period. Microhabitat significantly impacted average maximum daily temperature, the number of consecutive hours per day at or above 35 degrees C, and parasitoid emergence percentages. Parasitoid emergence declined significantly in response to increasing number of consecutive hours per day above 35 degrees C. Microclimate did not impact capsule discovery by predators or predation levels. Augmentation of T. exiguum for suppression of R. frustrana damage may not be practical within P. taeda plantations.

Operational Considerations for Augmentation of Trichogramma exiguum (Hymenoptera: Trichogrammatidae) for Suppression of Rhyacionia frustrana (Lepidoptera: Tortricidae) in Pinus taeda Plantations

Studies were performed to assess the operational feasibility of Trichogramma exiguum Pinto & Platner (Hymenoptera: Trichogrammatidae) augmentation for suppression of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lepidoptera: Tortricidae), in commercial loblolly pine, Pinus taeda L., plantations. Single inundative releases containing two cohorts of encapsulated T. exiguum at a potential rate of 224,200 ± 27,600 females per ha per cohort were made into two 4-ha plots during the second R. frustrana generation in 2000. Augmentation failed to increase parasitism rates above those occurring naturally; yet, 10% fewer shoots were attacked by R. frustrana, but not below acceptable levels. Quality control data suggest that low emergence levels and intense predation by ants upon developing T. exiguum lowered actual release rates to 13,000 ± 900 females per ha per cohort. The effect of capsule distribution and microclimate on the discovery of capsules by predators (indicated by some E. kuehniella egg removal), parasitoid predation (percentage of eggs removed or destroyed), and subsequent parasitoid emergence was investigated. Uniformly distributed capsules experienced significantly higher predation levels than clustered capsules, and capsules exposed to field conditions for 5 d experienced higher predation than those exposed for 3 d, independently of distribution. Discovery of capsules by predators was unaffected by distribution or exposure period. Microhabitat significantly impacted average maximum daily temperature, the number of consecutive hours per day at or above 35°C, and parasitoid emergence percentages. Parasitoid emergence declined significantly in response to increasing number of consecutive hours per day above 35°C. Microclimate did not impact capsule discovery by predators or predation levels. Augmentation of T. exiguum for suppression of R. frustrana damage may not be practical within P. taeda plantations.