Bruce Pyke (photo), General Manager, Research and Extension, Cotton Research & Development Corporation discusses the development of the Cotton Industries Insecticide Resistance Management Strategy for the 2005-06 season.

Bruce, it is the time of year that we are starting to think about the insecticide resistance management strategy for next season. Can you tell me what you are up to in terms of developing next year’s strategy?

The TIMS Committee has already looked at some of the resistance results from last season and although the numbers of Helicoverpa armigera eggs were pretty low, the general consensus was there has been no major changes with any of the key insecticide groups we were concerned about. So that’s good news. We felt that there was probably no need this year to then to go out and have a roadshow but we are still seeking industry feedback and part of that is the cotton consultants have offered to go around the different districts and get feedback from their consultants but we are still looking for feedback from growers if they want to comment on the strategy, most of the Cotton Growers Associations have a copy of it, all the extension officers have a copy of it, so its readily available.

The interesting thing that we have tried to do this year though is look at the situation of saying “well we have got 70% Bollgard®, it could well go higher in the future; is that going to make a difference to the way we might want to manage our insecticide resistance strategy?” and we have tried to look at it in that light and put out something that is a little bit radical. It’s a much more simple strategy and it’s only out there for discussion. It could well be that we might not even need to change things from what we had from last year. But what we are trying to do is to get something out there for people to comment on and say – “do you think this would work; is it too simple; have we changed things or suggested changing things too much; and perhaps are we loosing sight of our resistance management”.

You have been proactive in getting feedback about the previous years strategy and how it worked. What sort of comments have you had on last years strategy because it was a bit of a radical change from the season before?

In general terms I think people were reasonably happy with it and that could reflect the kind of season we had. We had quite a lot of pest pressure early from Helicoverpa punctigera in a number of areas that did require in a couple of cases requests to TIMS to bring forward pyrethroid use, but apart from that it was a very quiet season I guess in terms of the sort of issues that often come to the troubleshooting committee. So, I think that tends to reflect the fact that people coped quite well with what they had.

We have been attending a meeting today with some of the key researchers in resistance to Bt and conventional chemistry. What is some of the key information that is coming out? You said that the conventional chemistry hasn’t changed significantly in this last year. How about in the Bt’s?

The news there is also good. There is no evidence of any change from the previous season to the current season in terms of what can be detected and also so far with some of the screening that the researchers do to look at the new resistance gene that’s been detected to out of the second gene in Bollgard® (Cry2ab) they haven’t found any individuals yet in the nearly 700 test that they have done which is a good thing. 

A comment also that was made in the discussions was, ‘well now that we are up to perhaps 70% plus Bollgard®, should that reduce the potential for resistance to develop to the insecticides in the 30% of conventional?’ In affect the response from the researchers was ‘no that is not the case, it won’t make that much difference’. What it could do though is to reduce the overall size of the H. armigera population but it won’t necessarily reduce the potential to develop resistance.

So if you have got 30% resistance in a large population you are still going to have 30% resistance in a small population and the potential is there to affect the population at large if we do get another high pressure H. armigera year?

Yes, basically that’s the conclusion and so it is still, we can’t rely on Bollgard® as because of its potential sink for getting rid of quite a lot of heliothis out of the system its not going to really solve our resistance problem. So we have still got to maintain our rigor with all our resistance management for Bt cotton as well as for our insecticides.

How can growers, consultants or anyone provide feedback and be involved in the process of developing this years strategy?

Well the consultants will be holding meetings in different regions to gain that feedback. In terms of feedback from growers, they can do it either through their growers associations or they can do it directly with their local extension officer, provide feedback to them and they will get that back to the TIMS Committee.

Further Information: 
Dr Stephen Allen, Robert Eveleigh, John Marshall,  Craig McDonald, David Kelly or James Quinn