Sharing Knowledge in the Developing World: Ohio State Scientist Helps Fight Plant Diseases, Poverty

WOOSTER, Ohio – If knowledge truly is power, Ohio State University plant pathologist Sally Miller believes that sharing knowledge can help alleviate one of the most pressing issues facing millions of people in the developing world: being able to grow enough food to eat and make a living.

Miller most recently traveled to the West African nation of Senegal, where she taught at an international workshop on invasive species identification and management in the tropics, May 12-15, in the capital city of Dakar.

In Senegal, which is roughly the size of Nebraska, droughts are common and soils are poor, Miller said. Despite these adverse conditions, more than 60 percent of the country’s 13 million people, as in most developing countries, make their living by farming.

“We know that success in agriculture lifts people out of poverty,” said Miller, a professor and Extension specialist with the College of Food, Agricultural, and Environmental Sciences. “But there are many obstacles to success, including insect pests and diseases that rob crops of yield and quality, and farm families of food and income. 

“With globalization and climate change, we are seeing alarming shifts in the geographic range of crop-destroying plant pathogens and pests. Lack of experience in recognizing and dealing with these intruders, called invasive species, can result in severe crop losses.”

The four-day workshop was hosted by the Integrated Pest Management Innovation Lab (IPM-IL), a U.S. Agency for International Development-funded program managed by Virginia Tech. Miller is principal investigator for the International Plant Diagnostic Network (IPDN), a Global Theme project of IPM-IL.

The workshop hosted 33 participants from 11 developing countries, including from Africa, Southeast Asia and Central America. It concentrated on three important pests and diseases that have been impacting Senegal recently, and which are also present in other parts of the world: tomato bacterial wilt, the papaya mealybug and the tomato leaf miner.

Bacterial wilt, found all over the tropics, is very harmful to many important crops, including solanaceous vegetables -- which include the economically significant eggplant, tomato and pepper. In infested soil, these plants will grow almost up to the flowering stage, then die. Bactericides and fungicides fail to rid the soil of the bacterium that causes this disease, so farmers traditionally have had to abandon their crops on an infected tract of land and, if possible, move to another area.

“Farmers in developing countries often haven’t had the chance to learn about appropriate methods of dealing with plant diseases,” Miller said. “What we have found in our research is that simple interventions can have a huge impact on a farmer’s productivity. That’s what we tried to accomplish during this workshop.”

For example, the technique of grafting has benefitted tomato farmers dealing with bacterial wilt, Miller said.

“By using the relatively low-tech practice of grafting, farmers can still grow highly productive crops on bacterial wilt-infested soil,” she explained. “This is accomplished by grafting scions, or young shoots cut specifically for this purpose, on top of resistant rootstock, which allows farmers to overcome the disease,” she said.

The event included a hands-on grafting session led by Miller’s colleagues from the Institut Sénégalais de Recherche sur l’Agriculture. Miller’s Ph.D. student, Nagendra Subedi, also provided tricks of the trade for isolating and identifying the bacteria that cause bacterial wilt, using two suitcases full of supplies brought from Ohio.

Participants also learned about ways to identify papaya mealybug and tomato leaf miner from Rangaswamy Muniappan, a Virginia Tech expert on invasive insect pests and director of IPM-IL. Muniappan also described approaches to managing these pests by natural means, such as local or introduced natural enemies.

Finally, instructors and participants visited nearby farm fields and a wholesale produce market, where they found various tomato diseases, tomatoes infected with tomato leaf miner, and papaya mealybug. Samples were gathered to facilitate hands-on identification activities.

Training sessions such as the Senegal workshop are highly effective and a worthwhile investment, Miller said.

“How do we measure the success of these workshops? Within weeks after returning home, workshop participant Dr. Jesca Mbaka identified tomato leaf miner for the first time in Kenya, allowing KARI (the Kenyan Agricultural Research Institute) to begin intervention efforts.”

In addition to her tireless work researching and developing strategies for combating Ohio’s vegetable crop diseases, Miller has devoted time during the past decade to travel the world and help build capacity for plant pathogen and insect pest diagnosis and management through IPDN, which is funded by the U.S. Agency for International Development’s Feed the Future program. She has been involved in international agricultural development for more than 20 years.

The IPDN involves scientists from Ohio State, other U.S. universities and partner institutions in each of the network’s 12 member countries, located throughout the developing world.

Miller said this group has conducted 26 regional or international workshops since 2006, training over 500 plant scientists in classical and modern diagnostic techniques and management approaches. 

“By sharing knowledge we work to empower plant pathologists and entomologists in the developing world to meet the challenge of invasive species, and help farmers to mitigate damage to crops and livelihoods,” she said. “Farmer by farmer, the goal is to alleviate poverty.”

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