Set by three wise men!
As we are nearing Christmas this month’s quiz involves plants that are associated with the festive season. In the spirit of goodwill the quiz has been prepared collaboratively by Charles Lane (Fera Science), Alex Lewis (Forest Research), and Phil Taylor (CABI).
#1. Poinsettias are a very popular Christmas plant. However, they rely on a plant pathogen for their appeal. What feature of these poinsettias is due to a phytoplasma infection?
Answer: The short stem height. Wild poinsettias are tall plants well over 1.5m tall. It is infection by a phytoplasma that ensures the dwarf habit and makes them ideal pot plants.
#2. Holly foliage and berries is often used in Christmas decorations. One disease can cause a leaf blight and kill bark. What is this disease?
Answer: Phytophthora ilicis
Phytophthora ilicis causes holly leaf blight and is found only affects Ilex species. This disease can cause defoliation; leaf blotches and kill bark. Where holly has been planted in hedges, defoliation can appear as arches where the defoliation is at its widest nearer the ground.
© Crown copyright. Forest Research
#3. Diaporthe vaccinii is a fungal disease that threatens which sauce so essential to Christmas Day lunch?
Answer: Cranberry sauce. Diaporthe vaccinii is indigenous to North America. It has entered other continents with imported planting material of Vaccinium but has not in general established there. For example, it was found in Romania in experimental plots of introduced American cultivars but did not establish.
© Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org
#4. True firs (Abies spp.) are commonly grown as Christmas trees. Unfortunately, there is a disease which can cause severe cankers, leading to crown dieback and can potentially lead to the death of the tree. The organism responsible for the damage produces small, rounded, red fruit bodies (perithecia). What is the disease?
Answer: Neonectria neomacrospora. A fungal disease which can cause severe dieback and eventual death of true firs. Originally recorded in North America, there were old records of its presence in Europe (outside Denmark and Norway), although not causing severe symptoms. Although known to be present in the UK, reports have increased since 2015. Tree deaths have often occurred on fir species in landscape plantings, Christmas tree plantations, and forest stands.
© Crown copyright. Forest Research
#5. Leaf spot on sprouts: what clues seen in the photo indicate that this infection is due a fungus:
Answer: Small black dots within the infected area. Rings within the spot; the small black dots within the spot are fungal structures and the rings are common in fungal infections. Spreading from the edge of the leaf and limited by leaf veins are more generally associated with bacterial leafspots.
#6. What disease is this potato tuber suffering from?
Answer: Potato blight. Affected tubers have a reddish-brown decay below the skin, firm at first but often soon developing into a soft rot as the blighted tissues are subsequently invaded by bacteria. Light attacks of blight may not be visible on the tubers, but many infected tubers will rot in store.
© https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.40970
#7. Various levels of severity of Parsnip yellow fleck virus on parsnip. The aphid vector (Cavariella aegopodii) transmits PYFV in a semi-persistent manner but why is there no spread between plants within a crop of parsnips.
Answer: The virus requires a helper virus to be transmitted and this does not survive in parsnips. The aphids feed on parsnips and the virus is present but it is never spread from one parsnip plant to another.
#8. Current season needle necrosis is a condition affecting Abies in Europe and North America and causes chlorotic spots or bands which later turn necrotic on new growth around 2-4 weeks after bud break. What causes the disease?
Answer: Sydowia polyspora
The symptoms have been observed on noble fir (Abies procera), Nordmann fir (A. nordmanniana) and grand fir (A. grandis) on both continents. Under certain conditions, this fungus will function as a minor, weak foliar pathogen causing small foliar lesions. It is also associated with shoot and tip dieback and injury-related blue stain in several pine species.
© Crown copyright. Forest Research
#9. What is the common name of this long horn beetle that could threaten the supply of plum pudding?
Answer: Red necked beetle (Aromia bungii) is native to eastern Asia and poses a serious threat to a range of fruit and ornamental Prunus, as well as other hardwood trees. The larvae feed and tunnel under the bark and in the wood of both healthy and stressed trees and can affect fruit yield. Trees may be weakened or even killed after several successive years of infestation by this insect pest. The climate in much of the UK would be conducive to the establishment and spread of red-necked longhorn beetle, whose main pathway of entry to this country is via the live plant trade and in wood packaging material.
© Fera Science Ltd
#10. This organism has quite the history with uses described in Greek mythology, pagan rituals as well as being used in Christmas decorations. What is it?
Answer: Mistletoe (Viscum album) is a plant parasite with a broad host range. Most commonly found on apple it can also be found on lime (Tilia spp.) and poplar (Populus spp.). Widely used as a Christmas decoration, the use of mistletoe was recorded by Pliny the Elder who described the significance of mistletoe on oaks to Druids.
The Tree Council along with the University of Oxford and Fera Science are looking for participants for a citizen science survey to determine how abundant mistletoe is, and where it grows. More information can be found here: Be a MistleGo! Pioneer – Help us find the UK’s mistletoe this winter – The Tree Council
Results
We hope you enjoyed the quiz and learned something!
See how your score matches up…
1-3: You need to do a few more of these quizzes to become a field diagnostics expert.
3-5: You have made a start in your field diagnostics but there is some way to go…
5-7: You are getting more right than wrong so keep on learning!
7-9: Impressive you are getting pretty experienced in your field diagnostics!
10: Well done! But make sure you do the quiz again next month.
We hope you enjoyed the quiz and learned something!
See how your score matches up…
1-3: You need to do a few more of these quizzes to become a field diagnostics expert.
3-5: You have made a start in your field diagnostics but there is some way to go…
5-7: You are getting more right than wrong so keep on learning!
7-9: Impressive you are getting pretty experienced in your field diagnostics!
10: Well done! But make sure you do the quiz again next month.
