Crop Scene Investigation - 56: A five-alarm call from Steve's alfalfa field
Sunday, March 8, 2015
by BERNARD TOBIN
In his business, certified crop consultant Mervyn Erb says he doesn't get many five-alarm phone calls. But when Steve called Erb last May, the Clinton, Huron County, farmer had a genuine fear that the culprit would carve a path of destruction through his entire crop.
Over the phone, the farmer told Erb that something was "eating the heck out of one of my alfalfa fields." With a significant hay acreage in the area, Steve was fearful that the culprit would take out his crop.
That was enough for Erb. He headed out to get a closer look. "I arrived at Steve's field that morning and sure enough, it did look like heck. Chewed off alfalfa everywhere. A lot of plants appeared to be partly chewed off and were still hanging and attached."
Steve had seen alfalfa weevil in the past and wondered if the pest might be gaining a foothold in the field. But Erb quickly ruled that out because weevils typically just eat leaves off the top of the plant and there was also no evidence of the pest in the field.
Upon closer inspection, Erb did notice a high level of what he believed to be Common Leaf Spot or maybe Bacterial Leaf Spot on the alfalfa leaves. That wasn't surprising given the cool, wet, backward spring weather. But neither were the culprit. "Disease doesn't do this type of damage. The closer I looked, I realized that something was beating and ripping on the plant." He was puzzled.
Erb also concluded that the damage had happened all at once. Aliens? A poorly designed crop circle? A herd of rampaging deer? A feedlot full of cattle gone loose? A flock of Canada Geese now with an appetite for alfalfa? Vengeful groundhogs? He considered them all, but ruled out marauders. "No critter really half bites things like that; if there were critters, there would be manure and tramping all over the place." But there was no evidence.
The damage pattern was also a head scratcher. Steve had regularly driven past the field and noticed nothing odd until the day he spotted the devastation, which was confined primarily to a 60-foot-wide swath down the middle of the 30-acre alfalfa field.
As he continued his walk through the damaged area, Erb noticed plant stems that appeared bruised, with whitish and brown discolourations. "Some of these stems were partially kinked over and a lot of leaves appeared torn." He thought that was odd. A rainstorm wouldn't break off alfalfa stems, but wind and rain could tear leaves.
Erb then remembered past instances of similar symptoms in corn and soybeans that he had seen had over the years. About 6,000 acres were damaged in his area in 2013. Could this be the same culprit? He decided to head back to the farm and ask Steve about what type of weather he had seen in the past week.
At the farm, he ran into Steve's daughter, who managed the office. They were chatting about the weather when she asked Erb if he had experienced the same late night storm that they had seen earlier in the week. Erb said it must have missed his house – just seven miles away – and asked her to tell him more. It happened about 2 a.m., she recalled. "It was so violent, it woke up my kids."
Erb was convinced. There was only one thing that could have touched down under the cover of darkness and carved up Steve's alfalfa. Send your solution to Better Farming at: rirwin@betterfarming.com or by fax to: 613-678-5993. Please include your complete contact information. We can't ship a weather station to an email address!
Correct answers will be pooled and one winner will be drawn for a chance to win a Wireless Weather Station. The correct answer, along with the reasoning followed to reach it, will appear in the next issue of Better Farming. BF