Herbicide Resistance Gene In Black-Grass and Rye-Grass Identified

Black-grass (Alopecurus myosuroides), a serious weed of arable fields that is widley resistant to herbicides © Bas Kers, via Flickr (CC-BY-NC-SA 2.0)

Black-grass (Alopecurus myosuroides), a serious weed of arable fields that is widley resistant to herbicides © Bas Kers, via Flickr (CC-BY-NC-SA 2.0)

BBSRC (Biotechnology and Biological Sciences Research Council) and Syngenta funded scientists at the University of York and University of Durham have discovered a gene called AmGSTF1 that plays a key role in controlling multiple herbicide resistance in black-grass (Alopecurus myosuroides) and annual rye-grass (Lolium rigidum). Now the gene that confers resistance has been identified, it is hoped that chemicals that inhibit the gene may be able to be used in future to make herbicides effective against resistant weeds.

Black-grass and rye-grass are widespread weeds which cause problems in cereal and oilseed rape farming. Management using herbicides is becoming increasingly difficult since both black-grass and rye-grass can acquire a single defence mechanism that confers resistance to multiple herbicides- known as multiple herbicide resistance. The genetics of multiple herbicide resistance have been poorly understood until recently, however scientists have now discovered that a gene producing an enzyme called glutathione transferase (GST) is responsible for multiple herbicide resistance. Scientists created transgenic thale cress (Arabidopsis thaliana) plants with the GST producing gene inserted which were resistant. GSTs are known to detoxify herbicides, but project leader Professor Rob Edwards of the Centre for Novel Agricultural Products at the University of York believes that the gene they discovered works as a kind of ‘master switch’ that activates a range of protective mechanisms in the plant. When resistant plants with the GST gene are sprayed with GST inhibiting chemicals, they become susceptible to herbicides. This demonstrates the potential for using GST inhibiting compounds in future herbicide formulations to manage resistant rye-grass and black-grass. These weeds are currently very difficult to manage due to their widespread herbicide resistance.

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Plantwise Photo Of The Month – June

Plant clinic in Machakos, Kenya

Plant clinic in Machakos, Kenya © CABI

Photo Of The Month for June shows a plant clinic during market day at a village near Machakos, 50 kilometers outside Kenya’s capital city Nairobi. The photo shows a farmer showing a crop sample to a plant doctor, who is using his knowledge and reference material on the table to diagnose what is wrong with the crop and provide management information to the farmer.  You can read more about plant clinics in Kenya here

Black Rot Disease Hits Uganda

A photograph of a cabbage leaf showing symptoms of black rot. Image by USDA Forest Service via Wikimedia Commons (CC-BY 3.0)

A photograph of a cabbage leaf showing symptoms of black rot. Image by USDA Forest Service via Wikimedia Commons (CC-BY 3.0)

Vegetable farmers in the Kayunga and Mukono districts of Uganda are reporting crop losses due to black rot disease. One farmer, Twaha Kahooza of Kyampisi village, Kayunga Sub-county, says he had planted four acres of cabbages and was expecting about Shs18m (about £4,500 or US$7,000) from the harvest, however he only managed to get Shs5m (about £1,200 or US$2,000).

Black rot is caused by the bacterium Xanthomonas campestris pv. campestris and is one of the most destructive diseases of cabbage and other crucifers such as  broccoli, brussels sprouts, Chinese cabbage, collards, kohlrabi and mustard. The disease is usually most prevalent in low lying areas where plants remain wet for long periods. The disease is characterized by a yellow V-shaped lesion at the leaf margin which turns brown as the leaf area expands. The disease can also affect seedlings and can enter the plant through insect feeding or injury to the plant. Management of black rot in crucifers includes obtaining certified, pathogen free seed, ensuring there is enough space between plants and crop rotation.To read more about black rot and black rot management visit factsheets on the Plantwise Knowledge Bank.  

To read a Plantwise Factsheet for Farmers written in Uganda click here. 

To find out more about Plantwise plant clinics running in Uganda, click here

References:

‘Farmers count losses over black rot disease in cabbage’, Fred Muzaale, April 2013, Daily Monitor 

Agroecology – benefiting farmers around the world

Farmers is Malawi are realising the benefits of acroecology © CIMMYT ( CC BY-NC-SA licence)

Farmers in Malawi are realising the benefits of acroecology © CIMMYT (CC BY-NC-SA licence)

This week, the UK Minister of State for Agriculture and Food, David Heath, has announced his support for the use of agroecological farming methods which are seen as the foundation of sustainable agriculture. The International Assessment of Agricultural Knowledge, Science and Technology (IAASTD) define agroecology as “the science and practice of applying ecological concepts and principles to the study, design and management of sustainable agroecosystems”. In practice, this means simulating natural ecosystems and using low inputs to increase productivity.

In 2011 the UN reported that by using agroecological methods, projects carried out in 20 different African countries were able to double crop yields in 3-10 years. The projects also recorded a reduction in the use of pesticides, leading to savings for the farmers. The agroecological approach has multiple benefits, beyond these economic gains. It also takes into account social and environmental issues, including soil fertility, water availability and climate change.  Read more of this post

Improving Food Security Using Agroforestry Schemes

Agroforestry is an integrated system of trees and shrubs and/or crops and livestock within a managed agriculture area and has potential in improving food security in developing countries by fully utilising land, improving crop yields, diversifying farmer income and improving environmental sustainability.

Last month the United National Food and Agriculture Organisation (FAO) published an “Advancing Agroforestry on the Policy Agenda” guide, detailing case studies from countries including Kenya, Costa Rica, Ghana, Nigeria and Cameroon.

To read more about agroforestry and how it can be beneficial in farming systems see this recent article “How agroforestry schemes can improve food security in developing countries” by Caspar van Vark in The Guardian newspaper. 

Faidherbia is an indigenous African acacia which has been found to be useful in agroforestry systems due to the fact it sheds its nitrogen rich leaves in during the early rainy season when crops are being planting, thereby fertilising crops. Studies have found that Faidherbia-maize intercropping can increase maize yields by up to 400% in one area in Malawi. This photo shows Borassus palm intercropped with Faidherbia in Burkina Faso © Marco Schmidt via Wikimedia Commons (CC-BY-SA 2.5)

Faidherbia is an indigenous African acacia which has been found to be useful in agroforestry systems due to the fact it sheds its nitrogen rich leaves during the early rainy season when crops are being planting, thereby fertilising crops at an important time. Studies have found that Faidherbia-maize intercropping increased maize yields by up to 400% in one area in Malawi. This photo shows Borassus palm inter-cropped with Faidherbia in Burkina Faso © Marco Schmidt via Wikimedia Commons (CC-BY-SA 2.5)

Monitoring and Management of Desert Locusts in Africa

An adult Desert Locust © AtelierMonpli via Wikimedia Commons (License CC-BY-SA-3.0)

An adult Desert Locust © AtelierMonpli via Wikimedia Commons (License CC-BY-SA-3.0)

The United Nations Food and Agriculture Organisation (FAO) has this month warned that Desert Locust (Schistocerca gregaria) swarms are invading cropping areas of northern Sudan. The swarms originated from winter breeding areas on the Red Sea coastal plains and subcoastal areas in northeast Sudan and southeast Egypt. The situation requires close monitoring as more swarms are expected to form in the coming weeks that could move into parts of  Sudan and southern Egypt. If no further rains fall and the vegetation dries out, some of these swarms could move into the interior of both countries and also cross the Red Sea to the coast of Saudi Arabia.

Locusts belong to the Acrididae family (in the order Orthoptera which includes grasshoppers and crickets) and when triggered by certain cues such as increased crowding with other locusts have the ability to change their morphology, behaviour and physiology over several generations. This phase change occurs from a solitary to a gregarious phase, eventually causing the locusts to form dense hopper bands and swarms. One of the most serious locust pests is the Desert Locust.

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How The Gates Foundation and Carlos Slim are Supporting Innovation and Crop Improvement For Farmers

Carlos Slim, Bill Gates and Mexican Dignitaries visit CIMMYT to inaugurate the new Bioscience facilities © Eruviel Avila (CC-BY-NC-SA 2.0)

Carlos Slim, Bill Gates and Mexican Dignitaries visit CIMMYT to inaugurate the new Bioscience facilities © Eruviel Avila (CC-BY-NC-SA 2.0)

The Bill & Melinda Gates Foundation and Fundación Carlos Slim have announced a partnership in support of efforts by the Centro Internacional de Mejoramiento de Maíz y Trigo (International Maize and Wheat Improvement Center CIMMYT) in Mexico to develop and disseminate higher-yielding, more resilient wheat and maize varieties. Read more of this post

New Type of Invasive Whitefly Recorded In South Africa

The whitefly Bemisia tabaci (USDA image PD USDA ARS via Wikimedia Commons)

The whitefly Bemisia tabaci (USDA image PD USDA ARS via Wikimedia Commons)

A species of whitefly that transmits cassava mosaic virus has been detected in South Africa for the first time. The whitefly, Bemisia tabaci is a cryptic species complex containing some important agricultural pests and virus vectors. The term ‘cryptic species complex’ means that Bemisia tabaci is considered to be a complex of at least 24 different species that look almost identical but are in fact genetically different.  Researchers from a range of organisations including the University of Johannesburg, the University of Witwatersrand and ARC-Vegetable and Ornamental Plant Institute conducted surveys to investigate the diversity and distribution of Bemisia tabaci species in 8 provinces in South Africa. The study aimed to update the information regarding the different Bemisia tabaci types present in the country.

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What CABI Is Doing To Tackle Major Coffee Rust Outbreaks In Central America

Guatemala has declared a state of agricultural emergency after coffee rust fungus has affected approximately 193,000ha of coffee, equating to 70% of the national crop. As a result of the outbreak, Guatemala is releasing $13.7m (£8.7m) in emergency aid to help farmers buy pesticides and to inform farmers on ways to manage the disease. Honduras and Costa Rica have already declared national emergency and El Salvador and Panama are also affected.

Coffee is a major export crop in many Central American countries and it is thought that this disease outbreak, which has been called “the worst seen in Central America and Mexico” by John Vandermeer, ecologist at the University of Michigan, will lead to big job losses. The Institute of Coffee in Costa Rica has estimated that the latest coffee rust outbreak may reduce the 2013-2014 harvest by 50% or more in the worst affected areas.

To find out more information about coffee rust view our Plantwise Knowledge Bank- Coffee Leaf Rust PDF booklet.

Symptoms of Coffee Rust (Hemileia vastatrix) © Carlos Roberto Carvalho, Ronaldo C. Fernandes, Guilherme Mendes Almeida Carvalho, Robert W. Barreto, Harry C. Evans (2011): Cryptosexuality and the Genetic Diversity Paradox in Coffee Rust, Hemileia vastatrix. PLoS ONE 6(11): e26387. {{doi:10.1371/journal.pone.0026387}} (CC-BY 2.5)

Symptoms of Coffee Rust (Hemileia vastatrix) © Carlos Roberto Carvalho, Ronaldo C. Fernandes, Guilherme Mendes Almeida Carvalho, Robert W. Barreto, Harry C. Evans (2011): Cryptosexuality and the Genetic Diversity Paradox in Coffee Rust, Hemileia vastatrix. PLoS ONE 6(11): e26387. {{doi:10.1371/journal.pone.0026387}} (CC-BY 2.5)

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Plantwise Photo Of The Month – February

A farmer getting advice at a plant clinic in Nepal  © Dannie Romney/CABI UK

A farmer getting advice at a plant clinic in Nepal © Dannie Romney/CABI UK

To read more about plant clinics in Nepal and to watch a video of a plant clinic in action, click here.

To find out more about plant pests and diseases in Nepal visit the Plantwise Pest Distribution map 

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