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From Sentinel Plants to Trap Crops: our 8th online seminar

We were delighted to see a good number of members at our 8th online seminar, which featured two superb talks by Dr Wubetu Bihon Legesse and Dr Tom Pope. Here are some of the things we learned…

Dr Wubetu Bihon Legesse described a wide-ranging project to assess vegetable viruses in Mali…

Setting out to create a picture of vegetable viruses across Mali, Wubetu collected samples of African eggplant, okra, pepper and tomatoes with virus-like disease symptoms from all over the country. The team used  ELISA tests to identify the viruses within these samples.

The widest range of viruses by far were detected on peppers, and at least 17% of vegetable samples were positive for two or more different viruses – so there was a great deal of mixed infection. The most prevalent virus type was Begomovirus, which was found in two thirds of all infected samples.

Conversely, in about a third of the African eggplant, pepper and tomato samples, no virus was detected.

Sentinel plants – an excellent way to check on pests

A great way of checking for the presence of pests is to use sentinel plants, which can be planted near the crop and monitored for the presence of pests that have potential to cause damage.

Wubetu investigated if small plots of sentinel plants can be used to  reflect diseases present in adjacent crops, providing an early visual indicator of disease. Sentinel plants might include tobacco, quinoa or cowpea, these were planted alongside major crops such as tomato, pepper and African eggplant. This work  identified 13 plant viruses never reported before in Mali.


Some of the key takeaways from Wubetu’s talk were:

  • There are high diversities of virus diseases in vegetables in Mali
  • High Throughput Sequencing (HTS) technology is very useful for uncovering viruses, including novel viruses
  • Sentinel plants are a useful early warning system to spot plant diseases

Dr Tom Pope of Harper Adams University talked about cereal aphids…

Tom began by telling us that wheat yields in the UK have doubled in 60 years, although yields  have been plateauing over the last 20 years. Yield increases are due to the use of high yielding varieties, which demand synthetic fertilisers and pesticides. The trouble is that insect pests are becoming resistant to these, and many pesticides are being withdrawn due to human and environmental impacts. There are also fewer new pesticides being developed.

Barley yellow dwarf virus (BYDV) is a problem because it stunts plants and reduces stress tolerance. This virus could cost the industry £136M a year. It is primarily vectored by bird cherry-oat aphids (Rhopalosiphum padi) and English grain aphids (Sitobion avenae)

Given the situation with pesticides, the only way to stop this virus is through Integrated Pest Management (IPM), which is a holistic approach involving prevention, detection and control. Prevention might include measures such as delaying the crop so it misses the main flying season of vectors, and detection can include the use of forecasting tools. There is a gap in terms of pest control, as this is currently limited to synthetic pesticides.  

Researchers at Harper Adams University are  working on ways to stop insect vectors entering the crop, and the use of in-field monitoring (to find out if aphids are carrying the virus) and ways of attracting natural enemies of the vectors.  

Maris Huntsman wheat – a tempting treat for aphids

Researchers did some very interesting work on what makes a variety of wheat susceptible to viruses. They went back to an old wheat variety, Maris Huntsman, to understand more about what makes it more attractive to aphids than the more  modern recommended list varieties.

The work included surrounding a main crop of wheat with a ‘trap crop’ of Maris Huntsman to intercept and retain aphids.

The main takeaway of Tom’s talk is that future management of pests is about a diverse range of management tools – ie effective IPM. There is no ‘silver bullet’.

“It has been a wonderful day here with these astute presenters and colleagues. Let’s continue the networking for the betterment of our society!!!”

– Seminar participant

CONNECTED Members can log in and view the seminar here.