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Quantifying Pine Decline Update

Understanding the impact of pests and/or diseases on forest productivity and development of control measures are critical and technically challenging. In part, this may be attributed to the complexities of pest/ pathogen/ host associations as a whole, as well as the dynamic nature of the current growing conditions. Contemporary agricultural research is often conducted in controlled conditions over short periods focus on robust responses to isolated effects. Understanding tree responses to pests and diseases is more difficult requiring prolonged in situ observation of interactions among causal agents, environment, and biological processes within trees. The pests, pathogens, and hosts associated with pine decline in the southeastern U.S. stem from the strong association between poor crown health, root infection by pathogenic fungi and activity of root-feeding insects will be addressed in the proposed study. This project aims to understand how the pests and pathogens involved in pine decline interact with environmental factors and stand conditions to impact plantation productivity in order to account for and predict the economic losses attributed to these pest and diseases.

Long Term Goals:The goal of this project is to quantify the impact of pine decline on forest productivity so as to enable forest managers to make accurate predictions and appropriate management decisions about commercial stands that are affected by certain pests and pathogens.

Supporting Objectives:

1. Quantify the impact of fungal root infection on tree and plantation productivity and investigate the early detection potential of a subset of variables.

2. Determine the threshold level of fungal root infection required to cause growth reductions and mortality of plantation trees.

3. Examine the role of fungal root infection and its interaction with the water, nutrient, and carbon relations of plantation trees to determine the cause(s) of tree mortality and growth losses by the pine decline process.

4. Determine the impact of fungal root infection on the behaviour of bark beetles and other pests within affected stands.

John Mensah

Pests and diseases continue to pose a major threat to forest productivity in the US and other parts of the world. Within the southeastern US, southern pine decline (SPD) has been identified as one of the problems associated with loblolly pine. The project seeks to quantify the impact of pine decline on growth and productivity. This will enable forest managers and plantation owners to make appropriate decisions to minimize losses associated with SPD. It will further enhance our understanding of the interactions between the pathogen, loblolly pine and the environmental factors.

Jessica Ahl

As part of the Quantifying Pine Decline experiment in Eufaula, Alabama, my role involves looking at the insect diversity present in the stand over the course of the project. This is accomplished with a combination of insect traps, both ground and airborne based. Six panel traps are distributed throughout the study area, two each on either side and in the middle. These hanging traps made of black cardboard have a funnel and a cup of antifreeze in the bottom to capture flying insects. One type of pitfall trap used is baited with nothing but pine twigs and can capture small ground insects and bark feeding beetles and weevils; two of these are in each plot. The last kind of pitfall trap used is one with a wide mouth, capable of catching all sizes of insects, and also has a cup of antifreeze in the bottom; one of these in each plot finish up our traps. Traps are collected bimonthly and reset, and insects are stored in the fridge in the lab until they are sorted to family and then morphospecies. In summary of long term goals, we hope this will provide a snapshot of insect populations in stands affected by Leptographium terebrantis, providing greater insight into its understanding and management.

Shrijana Duwadi

In 2016, soil microbial biomass (MB) sampling was done in the winter, spring, summer and the fall in the project site in Eufaula, Alabama. In the same period of time soil moisture study was also done. The data collected were used to find the change in MB due to change in season and due to change in soil moisture content (SMC). MB sampling in 2017 will be used to access the change in MB due to inoculation of the trees with the plant pathogenic fungus (Leptographium terebrantis).In 2017, soil cores were taken in February to study the physical and chemical properties of the soil. Same process will be repeated in February 2018 to analyze the change in soil properties due to the inoculation. Soil cores will be collected in July and November 2017 to study the effect of the fungus on mycorrhizae. Root study which started in April 2017 and taken every 2 months will end on February 2018.