CROP SCENE INVESTIGATION – 20: What teamed up to damage Matthew’s corn?


When a field is doing poorly, a quick investigation may uncover a problem, but you need to be thorough in your assessment. Your diligence may reveal that several things are teaming up to take the sting out of your crop’s yield punch.

At the end of June, I received a call from Matthew, a Wellington county farmer who was puzzled by the unusual appearance of one of his corn fields. “The corn is much better along the roadway than the rest of the field,” he said. “The first 12 rows in from the side road are already at the 10-leaf stage. The plants are dark green and uniform in size. The rest of the field is yellowish and only at the 6-to-8-leaf stage. I think there is some kind of bug damage, too.”

Crops: CROP SCENE INVESTIGATION 19 – What caused Roger’s aphid infestation? – Solved


Soybean aphids are attracted to fields under stress. A soil test confirmed my hypothesis – that the soybean plants on the knoll of Roger’s field were stressed by a potassium deficiency.

Potassium-deficient soil can significantly reduce soybean yield and quality. On the flip side, potassium-rich soil can increase plant resistance to pests and diseases.   

Research in recent years has confirmed a link between potassium-deficient plants and soybean aphids, insects that thrive by sucking valuable nutrients from soybean plants.

CROP SCENE INVESTIGATION – 18 SOLVED: What’s been eating Bert’s seedlings?


What Bert initially thought might be frost damage turned out to be the work of wireworms. We found the long, cylindrical, copper-brown pest in the soil when digging up the damaged plants.  Wireworms are known to destroy germinating seeds and tiny seedlings, causing non-uniform growth or gaps in the stand. Plants appear wilted and leaves turn pale, sometimes becoming purplish-blue at the tips.

CROP SCENE INVESTIGATION – 19: What caused Roger’s aphid infestation?


The expression “more than meets the eye” often applies when there is trouble brewing in a soybean crop. This was certainly the case when Roger from Perth County called in late June.  

“My soybeans aren’t looking good in one part of a field,” he said. “The plants are discoloured. I haven’t had a chance to scout very closely, but I can see some are yellow and some are purplish-black.”

I agreed to head over after I’d finished another farm visit. So far, the growing season had been droughty and I’d been receiving lots of calls for agronomic advice.

CROP SCENE INVESTIGATION – 17 Solved: Bruce’s dilemma – to replant or not?


We had already established that frost was the root of Bruce’s problem. His corn plants were brown and wilted as a result of the temperature dipping to around -3 C for several hours. The tricky question Bruce faced was whether or not to replant.

There are a number of factors we had to weigh, including plant survival, loss of yield due to both potential lower stand and later planting date. After weighing all of these and looking closely at the plants, I advised him not to replant. And, indeed, after several days his crop outgrew its frost symptoms. The damaged leaves were replaced with new leaves within a week.



It was a chilly day at the end of May when I got a call from Bert in Glengarry County. He suspected frost damage in his corn crop. “We’ve had some pretty cold temperatures. I thought we’d be OK, but some of the plants in my field are turning white,” he said.

I agreed to go out and assess the frost damage on his seedlings. These calls typically involve me working with growers to evaluate whether replanting is in order. But what I found when I got to the field isn’t at all what I had in mind.

Bert’s stand was definitely thinning. The crop, which had reached the three- or four-leaf stage, had non-uniform emergence. But a closer examination of the affected plants told me that frost wasn’t a factor.

CROP SCENE INVESTIGATION – 16 SOLVED: Why are Rick’s beans defoliating?


Spider mites caused Rick’s soybeans to defoliate.

Also called two-spotted spider mites, the pests are tiny – approximately 0.5-1.0 mm in length  and thus barely visible to the naked eye. The eight-legged and yellowish-brown mites are rounded with two dark spots on the sides of the abdomen. They overwinter in sheltered areas, such as field margins and move into crops in the summer as their numbers build up.

Crop Scene Investigation – 17: Bruce’s dilemma: Replant after frost damage or hope for the best?


Early planting gives growers a great opportunity to maximize yields and get a head start on the growing season, but it can also put the young crop at risk of setbacks. My phone is always ringing in spring as I help growers through these challenges.

“My corn is brown and droopy,” said Bruce, on the phone from his Lambton County farm on May 14. The crop was planted early and had reached the three-to-four leaf stage. “We’ve had some pretty cold nights, so I’m thinking it’s frost damage, but I’d like your opinion.”

I agreed to go and take a look. On the way to the field, I considered the other possible problems. Herbicide drift or carryover could result in similar leaf symptoms.
“Why are you so sure it’s frost?”

Better Decisions: Does your farm business need an injection of creativity?

Harnessing your creativity and doing the proper planning are essential to developing the value-added ideas your farm business may need


This winter, up to 20 workshops on “Growing Your Opportunities – Quest for New Farm Value” will be offered across the province.

A major component of the workshop is to help producers identify a value-added idea which will assist them in building a profitable business. Ideas come from our own creativity and, as Gary Morton of Morton Horticultural Associates, the workshop author, explains, creativity comes from such basic human forces as listed in Figure 1.

Crops: CROP SCENE INVESTIGATION –15 : What caused wilted patches in Paul’s soybeans? – Solved


White mould, also known as sclerotinia, caused the wilted patches in Paul’s soybeans.

It’s fairly easy to make a visual diagnosis of this disease because of the white, cotton-like growth that develops on the affected plant’s stem. Stems and pods infected with white mould can also appear pale brown and water-soaked. Frequently, small black bodies (sclerotia) can be seen on the stems of diseased plants. Plants are generally killed in patches late in the growing season.