Set by Dr Phil Taylor.
It is spring in the UK and, before the importation of fruit and veg from all over the world, the first fresh produce eaten after winter was asparagus and rhubarb. They are the two crops in this months quiz.
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.
#1. What kind of insect are these rhubarb pests?
The correct answer is:
Plant bugs
These are hemipterans, the true bugs. They feed by sucking, but, unlike many other sucking pests, they often inject toxins into the plant and cause tissue death.
Photo credit: Whitney Cranshaw, Colorado State University, Bugwood.org
#2. What has caused the ghostly patterns on this rhubarb leaf?
The correct answer is:
Viral infection
The symptoms seen here are due to Tobacco streak virus. It has a wide host range and produces a variety of symptoms including tissue necrosis on some hosts. It can be spread by both seed and, most unusually, pollen in some hosts. The insect vectors are thrips.
Photo credit: V Anette Phibbs, WI Department of Agriculture, Trade & Consumer Protection, Bugwood.org
#3. What has caused this bunchy growth in these asparagus plants?
The correct answer is:
Aphid attack:
Very surprisingly (for me at least) these are the symptoms of the asparagus aphid Brachycorynella asparagi. It is extremely unusual for an aphid colony to cause this kind of alteration to the growth habit of a plant.
Photo credit: Whitney Cranshaw, Colorado State University, Bugwood.org
#4. What has caused the lesion on this asparagus stem?
The correct answer is:
Fungal infection:
The strong border indicates a fungal infection but the fruiting bodies within the lesion put it beyond doubt. This infection is caused by Phaeosphaeria spp.
Photo credit: Cesar Calderon, USDA APHIS PPQ, Bugwood.org
#5. What are these?
The correct answer is:
Insect eggs:
These are the eggs of the asparagus beetle, Crioceris asparagi, potentially a serious pest of asparagus.
Photo credit: Ward Upham, Kansas State University, Bugwood.org
#6. What kind of insect is this rhubarb pest?
The correct answer is:
Coleopteran:
Coleoptera is the Latin name for the beetle family of which weevils are a subset. This is the adult rhubarb curculio Lixus concavus. It feeds on rhubarb and lays eggs on rhubarb but the eggs laid in rhubarb do not hatch, but are killed by the sap or crushed by the developing tissues. The plant that supports the growth of the larvae are dock plants.
Photo credit: Kansas Department of Agriculture, Bugwood.org
#7. What is causing these lesions on this asparagus stem?
The correct answer is:
Fungal infection:
These lesions are due to Cercospora leaf spot caused by Cercospora asparagi. Symptoms are small, oval, grey to tan lesions with reddish brown borders on the needles and small branches. Spores of the fungus are produced on the lesions and are dispersed by wind and rain.
Photo credit : Brian Olson, Oklahoma State University, Bugwood.org
#8. Asparagus rust caused by Puccinia asparagi is an autoecious macrocyclic rust fungus. What does this mean?
The correct answer is:
It completes its whole lifecycle on asparagus and goes through the full compliment of spore types.
“Autoecious” means it has only one host and “macrocyclic” means it has all the spore types seen in rust fungi. Asparagus does have males and females but both are equally susceptible. As for all rust fungi, it is not possible to culture it in the laboratory.
Photo credit: Wikipedia.
#9. These are viral ringspots on rhubarb. Which viral vector is commonly associated with viruses that cause ringspots such as these?
The correct answer is:
Nepoviruses are spread by nematodes and often induce ringspots in the host.
Photo credit: P. Taylor CABI
#10. Weed control in rhubarb can be difficult, but why is it important not to use glyphosate on a rhubarb crop?
The correct answer is:
Rhubarb is extremely sensitive to glyphosate and the slightest exposure will kill it:
The sensitivity of rhubarb to glyphosate is remarkable, I know this to my cost. The slightest bit of drift will kill the rhubarb outright.
