I did some the other day but my numbers were much higher than that over 100 so i thought it would be worth while. I wouldn't spray at those number killing too many good bugs with the bad ones. Just my opinion... I didn't spray any fields that didn't have over 100.
What size are the bugs, are you finding mostly darker adults or lots of medium sized and little ones as well ?. As far as what damage you already have, do you see much for the sticky spots on your pods or finding much damage when opening pods from top to bottom of plants ?.
We ended up getting all of ours sprayed this year by air as we had anywhere from 60 to over 100. Even though we sprayed there was still damage that occurred but we've had high counts before and missed the boat on spraying a high infestation in a field and oh did it ever do damage, downgraded because of brown seeds that rolled out and the bushel weight was noticeably lighter.
Do you have a lot of seeds that are not much more then bags of water or have they firmed up, even on the top pods as that crop staging does make the difference to how bad the damage will be. If it was us and we had those counts and still found a lot of soft seed, we would get it sprayed and prefer to have it done by air to avoid the trampled crop and plugging the swather header because of tracks.
Northern Farmer there are about 50% dark ones and 50% bigger green ones. I wasn't counting little ones. The bottom pods are full and healthy. The upper pods are showing some damage.
I was just wondering how much more damage could occur? And ya, 3-4% loss from wheel damage plus cost of spray could equate to $30 per acre. By air would be approx $18? per acre. Will they take more than 3 bu per acre from now until swathing?
The pods that I had were sticky your hands felt like you were handling spruce limbs, and puncture wounds could be seen from damage that had been done already. I hope that I caught them in time, pods were still fairly soft and had just come out of bloom about 4-5 days. Still aways from swathing.
That is a tough call but the 30 to 40 really is higher then that as we count all of them no matter how small as they grow fast and they get hungry. The per acre rate we have paid in the last couple of years ( yes we sprayed quite a bit last year too ) is $10 for the plane and then add chemical on top of that of which was $620.00 per jug and does 110 acres so $5.64 per acre there. We used the CPS chemical this year called Silencer which really is Matador and so far we swathed one field just today and looking at the knife there was not one bug on it of any sort ( which isn't right by nature but goes to show the chemical worked ). But going along a headland pass beside the neighbor who didn't spray my brother saw many bugs crawling on the steps leading into the swather ... one wonders what damage he has then.
The fact is more then half of the bugs in a sweep count were small ones and its hard to time it right as more hatch or have they already hatched.
Most of our canola was past the bloom by the time of spraying but one field was lagging on with some blooming and yet lots of bugs in it as well. Farmercook, sounds like you will certainly have damage in your canola stand but had you not sprayed, you wouldn't want to see what that looks like with those numbers.
What I don't know is if some farmers are kidding themselves when saying that they felt the pods had toughened up and wasn't worrying about spraying. It is just a crappy deal all around though when one has those bugs, dammed if you do, dammed if you don't.
Thanks guys for your replies. I hate killing all those insects, but right now the canola is my best looking crop. And ya, in 2012 I had 50bu swaths that yielded 30bu (lygus, bertha and sclerotinia, and oh ya, aster yellows). NEVER want to have that happen again.
The Canola Council of Canada has raised counts to 43 so the 100 is plenty high.
But on the other hand as already pointed out the killing of the beneficials when spraying may put one on the chemical treadmill and I'm not remotely interested in that.
Don, that is what I've thought different times as well and sometimes its leaned that way, canola on canola for instance causing more flea beetles or lygus but none of that flew this year, not even the having sprayed last year aspect as we had them just as bad if not worse on what had been wheat last year. The neighbor as well, he never sprayed anything last year, never had any canola on canola this year and was totally shocked as he was finding over 100 bugs and some of his fields are near here while others are a number of miles away.
I know berthas can invade a whole area as they lay their eggs and then we are in for a rude awakening when someone screams BERTHA !, go out into the field and see them chewing away. I hate it though, we never used to have to spray very often and perhaps its because there is more canola grown now then their used to be but also because of the chemical taken off the market that worked so well on the canola for the flea beetles which now forces us into spraying in the spring sometimes.