> ## Content Index
> Fetch the complete content index at: https://www.foodconsumer.org/llms.txt
> Use this file to discover other available public pages before exploring further.

# Compound from Bacteria Could Be Useful Against Pecan Scab
- URL: https://www.foodconsumer.org/compound_from_bacteria_0917141002/
- Published: 2014-09-17T11:01:00.000Z
- Updated: 2026-09-15T14:25:10.000Z
- Description: USDA scientists found that bacteria living in the guts of beneficial nematodes make compounds that suppress Fusicladium effusum, the fungus behind pecan scab. The most toxic extract contained trans-cinnamic acid, active at low concentrations in lab cultures.
- Author: Food Consumer
- Tags: Agriculture, Environment, #vivvo-import

## Compound from Bacteria Could Be Useful Against Pecan Scab

By [Sharon Durham](http://is/contacts.htm?ref=foodconsumer.org#Sharon)  
September 17, 2014

Bacteria that live inside the guts of tiny nematodes could hold the key to controlling pecan scab, a major fungal disease that affects pecan production in the southeastern United States.

[U.S. Department of Agriculture](http://www.usda.gov/wps/portal/usda/usdahome?ref=foodconsumer.org)(USDA) scientists discovered nematode-dwelling bacteria that produce chemical compounds that control the fungus *Fusicladium effusum*, which causes pecan scab.

[Agricultural Research Service](http://www.ars.usda.gov/main/main.htm?ref=foodconsumer.org) (ARS) plant pathologist [Clive Bock](http://www.ars.usda.gov/pandp/people/people.htm?personid=45215&ref=foodconsumer.org), entomologist [David Shapiro-Ilan](http://www.ars.usda.gov/pandp/people/people.htm?personid=12032&ref=foodconsumer.org), chemist [Charles Cantrell](http://www.ars.usda.gov/pandp/people/people.htm?personid=36215&ref=foodconsumer.org), and plant pathologist [David Wedge](http://www.ars.usda.gov/pandp/people/people.htm?personid=5964&ref=foodconsumer.org) examined chemical extracts of the bacteria to identify the major components responsible for suppressing pecan scab. ARS is the USDA’s chief intramural scientific research agency, and this research supports the USDA priority of promoting international food security.

Bock and Shapiro-Ilan work at the [ARS Fruit and Tree Nut Research Laboratory](http://www.ars.usda.gov/main/site%5Fmain.htm?modecode=66-06-05-00&ref=foodconsumer.org) in Byron, Georgia. Cantrell and Wedge work at the [ARS Natural Products Utilization Research Unit](http://ars.usda.gov/main/site%5Fmain.htm?modecode=64-08-10-00&ref=foodconsumer.org)in Oxford, Mississippi.

The bacteria, according to Shapiro-Ilan, live in the guts of beneficial nematodes in the genera *Steinernema* and *Heterorhabditis*. The bacteria are critical in helping the beneficial nematodes kill their insect hosts, and can be grown in petri dishes. Extracts of the cultures contain antimicrobial metabolites that are active against a wide range of microbial pathogens of animals and plants, including bacteria and fungi.

The extract found to be most toxic to the pecan scab fungus was purified and found to contain trans-cinnamic acid. Laboratory test results showed that trans-cinnamic acid was toxic to the pecan scab fungus in amounts as low as 148-200 micrograms per milliliter in solid culture and 64 micrograms per milliliter in liquid culture.

Conventional chemical fungicides have been widely used to control pecan scab, but in some growing seasons, more than 10 sprays are required to ensure adequate control of the disease on susceptible pecan cultivars. As a result, *F. effusum* has now developed resistance to at least two classes of fungicide, according to Bock.

This work was published in the [*Journal of Pest Science*](http://www.springer.com/life+sciences/entomology/journal/10340?ref=foodconsumer.org) in March 2014.