Set by Dr Phil Taylor
It is the end of the year and, as we are near Christmas, I thought we would have a quiz involving plants that are associated with Christmas in one way or another (well, they are linked with Christmas in UK albeit a little tenuously). Some questions are easy, some hard and some I am expecting you to tell me I am wrong.
#1. What is causing the dramatic leaf spot on this ivy leaf?
#2. Mistletoe is green and can photosynthesise. What effect does it have on the host tree?
The correct answer is:
It has a very damaging impact on the health of the plant but localised to the place of infection.
Despite the ability of mistletoe to photosynthesise, it does draw a lot of photosynthate and minerals from the host tree. Epiphytes are plants that use larger plants for support, but this is a parasitic plant, draining resources from the tree.
#3. What is the yellow area on this holly leaf?
The correct answer is:
Leaf miner tunnels
Holly leaf miner (Phytomyza ilicis) is a common pest of holly in many areas. It is generally considered not to cause a great deal of damage.
#4. A disease of pine trees, how is this symptom best described?
The correct answer is:
Most of us are more familiar with pustules on broad leaved plants, but pines get rusts too. This is Rhabdocline needlecast caused by Rhabdocline weirii on Douglas fir.
Photo credit : Dawn Dailey O’Brien, Cornell University, Bugwood.org
#5. This is the adult phase of the white pine weevil on a spruce branch. What specifically is the correct name for its juvenile form?
The correct answer is:
Grub
Larva describes all forms of juvenile insect which are yet to undergo metamorphosis. A “pupa” describes the transition phase, for some insects, between larva and adult. “Maggot” is a term used to describe the larva of true flies.
Beetle juvenile forms, including weevils, can often be described as “grubs”.
“Worm” is more commonly used in biological terms for invertebrate animals including e.g., the annelids (earthworms, etc), nematodes (roundworms), and flatworms, with slender elongated, legless bodies. Common names often add to the complexity e.g., the “Silkworm” is a juvenile moth and the “Wireworm” a juvenile beetle.
#6. This is Boswellia sacra, the tree from which frankincense is produced. Why does the tree produce the resin which is dried into frankincense?
The correct answer is:
It has never been determined:
There is a huge amount of data on the medicinal uses of frankincense but there is no research (as far as I can tell) on the benefits to the tree.
#7. A yule log is often a chocolate swiss roll but was a special log burnt at Christmas: it could have been many kinds of wood but was often oak or birch. What type of pathogen is attacking this oak tree?
The correct answer is:
The only fungi that produce large fruiting structures such as toadstools, mushrooms, or (as in this case) brackets, are the Basidiomycetes.
Photo credit : Andrej Kunca, National Forest Centre – Slovakia, Bugwood.org
#8. Cranberry is often eaten as part of a traditional Christmas meal, with turkey, but what has happened to this cranberry leaf?
The correct answer is:
This is Diderma simplex, a slime mould: one of those fungi that are almost not fungi and are extremely atypical of this biological Kingdom. It is said that there are no plant pathogenic slime moulds. I will let you do the research to find out if this is true.
Photo credit. Bruce Watt, University of Maine, Bugwood.org
#9. Sprouts are often eaten as part of a traditional Christmas lunch, but what is on the surface of these sprout leaves?
The correct answer is:
Ice crystals:
Frost has come down and coated these leaves with a wonderfully delicate array of crystals.
#10. Figgy pudding is the original name for Christmas pudding? What do you think is causing the leaf spots on this leaf of edible fig?
The correct answer is:
Fungus:
This is Cercospora leaf spot of fig caused by Cercospora fici.
Perhaps the most classic of leaf spotting fungi, these are the symptoms of Cercospora.
Note the strong border and the contained aspect of the spots, it does not look like they are going to engulf the whole leaf.
Photo credit: Jonas Janner Hamann, Universidade Federal de Santa Maria (UFSM), Bugwood.org
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.
