Blog written by PT Bandara, CABI Associate, and WMDH Kulatunga, Sri Lanka.
“A looming threat imposed by Salvinia molesta was averted through the introduction of a biocontrol agent by technical experts of the Department of Agriculture.” These were the words of Project Director Engineer RB Tennakoon, of the Moragahakanda Kaluganga Development Project, Sri Lanka; a project with the key objective to improve the availability of irrigation to water-scarce farmlands and thereby increase crop production and productivity in the area surrounding Kaluganga and Moragahakanda reservoirs, as well as supplying domestic water to Anuradhapura, Trincomalee and Matale districts.
Salvinia molesta recently replaced Rinderpest virus on the list of “100 of the world’s worst invasive alien species” in a global survey conducted in 2013 where over 650 invasion biologists participated. It is a water fern which forms dense mats over water reservoirs and slow moving rivers, causing large economic losses and a wide range of ecological problems to the environment, native species and communities. It can clog water intakes and interfere with agricultural irrigation water supply and hydropower generation.
One of the water tanks at Kaluganga was completely covered with Salvinia in March 2014 and there was a huge possibility of spread of Salvinia throughout the irrigation system of Kaluganga Project. The case was referred to the Plant Protection Service of the Department of Agriculture. Within ten months the tank was clear of Salvinia, without the use of any mechanical tools or chemicals but using a control method perfectly compatible with nature. What made this possible?
It is due to a tiny weevil Cyrtobagous salviniae used as a biocontrol agent. Larvae of C. salviniae tunnel within the rhizomes/stem causing them to disintegrate. Larvae also tunnel in the buds and adults eat buds, thus suppressing growth and vegetative propagation of this sterile weed. Technical experts from the Plant Protection Service of the DoA, who are responsible for rearing this weevil provided a culture of the biocontrol agent and introduced them into the infested water bodies.
The elimination of this troublesome weed led to the jubilation of the Project Director. Mr Tennakoon acknowledged the support given by Mr PT Bandara, Deputy Director Plant Protection Service at the time of this project, and his team in removing this highly invasive water weed and thus eliminating a huge threat that would have jeopardized the Moragahakanda Kaluganga Project.
In recent years, Tuta absoluta has gained a reputation for being one of the most destructive pests of tomato and can cause losses of 80-100% in the field if left unmanaged. Tanzania are feeling the effects of the yield reduction with a 375% increase in the cost of tomatoes in the past 6 months. A carton of tomatoes that cost Sh16,000 ($9.4) in January 2015 now costs around Sh60,000 ($35.3). Vivian Munisi, a trader at Tanzania’s Arusha central market, is just one of the people who are expecting the price of tomatoes to increase further in the coming months as a result of the shortfall caused by T. absoluta.
The larvae of T. absoluta, which is also known as the tomato leaf miner, bores into leaves and fruit and feeds below their surface, forming mines as they move along the plant. The network of mines produced as a result of this feeding can also serve as an entry point for disease, which can lead to further damage. Although tomato is the main host for the tomato leaf miner, it can also affect potato and other Solanaceae plants. The pest originated in Latin America but has spread to Europe, Asia and more recently, Africa where it has caught smallholder farmers unprepared.
There are a number of management options that will help to reduce the damage caused by the tomato leaf miner. These include disposing of infested fruit, setting pheromone traps and applying sprays of either biocontrol or a chemical pesticide. To find out more about tomato leaf miners and how these sprays can contribute to their control, read this month’s Plantwise Factsheet for Farmers which was written by an Agriculture Officer from the Ministry of Agriculture, Food Security and Cooperatives (MAFSC) in Tanzania. Tomato production in Tanzania has been badly affected by the tomato leaf miner. Continue reading →
Blog written by Dorcas Kabuya Chaaba-National Agricultural Information Services,Zambia
Rallies are commonly associated with politics, a time when politicians present their ideologies to the electorates in a bid to win votes. But this time around, officers from the Ministry of Agriculture and livestock implementing the Plantwise initiative in Zambia held plant health rallies with farmers to share management solutions on specific crop problems.
Drawn from different districts of the country, these officers who are trained plant doctor held plant health rallies in Rufunsa, Chongwe, Chilanga districts of Lusaka Province while in Central Province the same events took off in Chibombo and Kapiri Mposhi. Farmers who attended the rallies were sensitized on how to control various pests and diseases of groundnuts, cotton, cabbage, tomato, maize and sweet potatoes.
The goal of these rallies was to create awareness of the Plantwise initiative that was launched in May 2013 with an additional focus of advising farmers how to manage pests and diseases reported in the places where the initiative is currently running plant clinics.
The production of food is taken for granted by a lot of people. But to farmers, producing a healthy crop that can give them income at the end of the day can be a challenge. Pests and diseases if left unattended to can have serious consequences. As such, farmers need to be equipped with the necessary knowledge to fight pests and diseases if this problem is to be contained. Plantwise addresses the constant struggle that small-scale farmers go through to produce food by providing affordable, locally available solutions to plant health problems. Plant clinics are at the heart of Plantwise and trained plant doctors diagnose pests and disease problems brought by local farmers using plant samples on a one on one basis, during the plant health rallies, farmers came in large numbers and were helped by Plant doctors.
Clinics and rallies help farmers to access the information they need when they need it and it further helps them reduce crop losses thereby improving crop health and their livelihoods.
Improving food security is not a myth – using the right agricultural extension approaches surely, we can loose less and feed more!
Here’s a taste of some of the latest stories about plant health, including bacterial blight affecting pomegranate quality in India, women in Kenya growing crops in sacks to feed their families and a pledge from China’s Ministry of Agriculture to reduce fertiliser and pesticide use and improve water conservation.
Growing up in a small village in Western Kenya, I often accompanied my mother and other village women on customary weeding expeditions. Whenever we came across sick plants in the fields—which was all too often—my mother would instruct me to pull them out and cast them aside.
I did as she asked, but wondered to myself: Why do we simply throw out the plants instead of doing something to make them better?
At times, my mother lost nearly 80 percent of her tomatoes to plant disease. The loss was so bad that she eventually stopped growing tomatoes all together. Yet when one of our cows got sick, my mother would call a veterinarian to come and treat the cow. I wondered: Were there no doctors who could also cure our plants?
I turned this curiosity into a career in science and became the first child in my family to attend university as well as the first woman in my village to earn a science degree. Seeking answers to my childhood questions, I studied botany and zoology as an undergraduate to better understand the diversity of crop and animal pests and diseases afflicting farmers like my mother in Kenya and her peers across Africa. I wanted nothing more than to find a practical solution.
We’ve selected a few of the latest new geographic, host and species records for plant pests and diseases from CAB Abstracts. Records this fortnight include new distribution and host records for white coconut scale (Parlagena bennetti), fungi associated with black mould on baobab trees in southern Africa and two new Uropodina mites from a pine plantation in Kenya.
Here’s a taste of some of the latest stories about plant health, including Theni banana farmers in Tamil Nadu adopting more efficient production techniques, why GM crops have been slow to take hold in Africa and the bio slurry pellet method of rice cultivation that could save farmers time and money.