Try your hand at these questions. Answers are in the Purdue University Corn & Soybean field pocket guide. We've even included the correct answer and page number of the 2011 guide where you can find the answer after each question.
1) If 50% of corn leaf area is destroyed at 10-leaf stage, expect ___% yield loss
a) 6 b)15 c) 25 d)35 e) 46 (a, 34)
2) If hail knocks out 60% of leaf area in corn at late dent, expect ____% yield loss.
a) 7) b)25 c)35 d)45 e) 57 (a, 35)
3) Silk receptivity to pollen decreases rapidly after
a) 2 (days) b) 4 c) 5 d)10 e) 25 (d, 39)
4) Stage that occurs 10 to 14 days after silking is (e, 41- if you marked d, subtract 10 points)
a) Milk b) dent c) dough d)roaster e)blister
5) If the whole plant is killed by a freeze with corn kernels in soft dough stage, ___% yield loss
a) 35 b) 27 c) 55 d) 6 e) 12 (c, 47)
6) No more starch can enter the kernel once the _______layer forms.
a) Brown B) Black c) red d) white e)gold (b, 46)
7) If there are 32,000 plants per acre and 600 kernels per acre, factor, yield estimate is
a) 173 (bu/acre) b) 193 bu/acre c) 213 bu/acre d) 313 bu/acre e) can't determine
8) If you have 1,000 bushels of 26% corn in the field, you really have ____dry bushels
a)1,000 b) 500 c)870.6 d) 830.6 e)can't determine (c, 50)
9) If you harvest 1,000 bushels of 26% corn from 5 acres, the dry yield is:
a) 200 bu/acre b) 174 c) 195 d) 85 e) can't determine (b, 50)
10) The test weight for U.S. No. 1 yellow corn must be at least ____pounds per bushel.
a) 54 b) 56 c) 58 d) 60 e) 75 (b, 52)
11) Softball sized hail in July can (e, 57)
a) strip leaves b) kill plants c) produce ear injury d) none of these e) all of these
12) Purplish corn at young stages can be caused by (e, 58)
a) phosphorus deficiency b) cold soils c) compaction d) potassium deficiency e) all but d
13) Begin scouting for anthracnose leaf blight in (d, 58)
a) May b) June c) July d) August e) Scouting is a waste of time
14) White grub later become (a, 61, know it)
a) Japanese beetles b) corn borers c) rootworm beetles d) wireworms e) click beetles
15) The first time you see a black cutworm larva in a corn field, you should (c, common sense)a) call 911 b)hire aerial applicator c) plan scouting d)expect lower yields e)panic