Symphylans and Salinity: Management of the Greenhouse Maureen Copeland Summer, 2003 Penn State AgroEcology Internship

Problems at Sonnewald Farm Plants suffering in Old Greenhouse during 2002 Thought to be caused by symphylans

Symphylans: Overview Food: Organic matter (e.g. plant roots, sprouting seeds) Migrate vertically through the soil; found in depths up to one meter deep

Organic Matter % Organic Matter New Greenhouse18.8 Old Greenhouse14.7 Outside Garden13.9 “Typical farm”1-8

Hypothesis Lower organic matter will reduce the symphylan population- less food Lower salinity will improve plant growth & provide a better habitat for predators, reducing symph population

The Treatments Control (greenhouse soil) Intermediate soil (1:1 greenhouse to outside soil) Most diluted soil (2:1 ratio) Low salinity

1:1 Low Saline 2:1 Control Low Saline Control 2:1 Low Saline 1:1 2:1 1:1 Control Plot Setup Replicate 1Replicate 2Replicate 3

What I did Set aside one bed in the Old Greenhouse for experiment Planted with Ermosa lettuce in each plot after taking initial soil samples Took 2 types of samples on 3 days – June 16, July 13, and July 30

Methods Symph bait – use beet slices under a container for 24 hours to collect soil arthropods From:

Methods Berlese Funnel: take small soil samples and place in a funnel with light on top – Light drives organisms downward into vial of alcohol

Results One symph found in all the samples taken – Where did they go?

Most diluted soil= more organisms? 2:1= 2parts outside soil : 1 part greenhouse soil 1:1= 1part outside soil : 1 part greenhouse soil

More Results Average weight of lettuce (lbs) Control0.32 Low Salinity0.35 Intermediate soil (1:1)0.47 Most diluted soil (2:1)0.48 Difference between control and most diluted soil is significantly different

Further considerations Temperature: – Earlier samples- higher abundance Leaching out salts: leach out nutrients? Low OM is still high compared to “typical farms”

Interpretations Possible that symphs migrated downward during warmer summer season – Supported by evidence that deep soil samples had more symphs than any other samples Does not explain some things…

Are Symphylans really the problem? This season- pepper plants in new greenhouse are struggling – no symphs found Measured EC

EC & Salinity Average ECSalinity Healthy Peppers Average Peppers Unhealthy Peppers

Salinity & Bugs Salt level appears to be affecting diversity of soil dwelling organisms # of different species found in bait samples Good Peppers 14 Bad Peppers4 From:

How does high salinity occur? Manure inputs: – Compost with manure had higher level of salts than plant-only compost Manure compost= 1.47mmhos/cm Plant-based compost= 0.29mmhos/cm Lack of rain: salts are not leached

What this means Possible that symphs were causing some of last years damage. However… More likely that combination of high salinity & symphylans stressed greenhouse crops