I’ve made a number of comments about controlling plant bugs on pre-flowering cotton in previous blog articles (linked below). Tarnished plant bug infestations continue to remain above average in many fields. Rain is aggravating the spray logistics and reducing residual control. The only thing I can add is that repeated sprays will be necessary in some situations. Even under ideal conditions, retreatment may be needed in as little as 5-7 days and especially in scenarios where retention is relatively poor (<80%).
Questions continue about tank mixing to improve control. The reality is that two applications will be better than one when tarnished plant bugs are continuously migrating into fields. However, field reports are clearly indicating that the imidacloprid products are not providing as good of control as Centric at 1.5 – 2 oz/acre (at least when infestations levels are high). I am also hearing that Centric is in short supply. This may force some tank mixes in scenarios with high pressure and poor square retention. For resistance management purposes, UT recommends avoiding OP and pyrethroid insecticides prior to bloom, but we have to do what is necessary to maintain adequate square retention. Below are some tank mixes to consider. I still suggest avoiding combinations with pyrethroid insecticides. We already have issues with pyrethroid resistant populations of tarnished plant bugs We need to save pyrethroids as a tank mix partner for later in the season.
Potential tank mixes and other options for “emergency” control plant bugs are listed below. These are options intended for heavy infestations. By using the mixes below, the imidacloprid component will help to prevent the flaring of aphid populations. Intruder is also listed in our control guide for plant bug control, but I only recommend this product in circumstances where aphids infestations are the primary target. Reminder: Bidrin can NOT be used between first square and first flower.
Options for “emergency” control of plant bugs in prebloom cotton:
2 oz of Centric . If you can only find a little Centric, you might consider spiking a full or near full rate of an imidacloprid product with 1 oz of Centric to stretch the supply.
Vydate at 10 – 16 oz (12 oz would be a good starting point) but be aware that this may flare aphids.
Acephate/Orthene at 0.67 lb/per acre. This is a relatively cheap alternative but a likley choice to flare aphid or spider mite infestations.
Belay at 4 oz/acre (see below).
Remember, the treatment threshold for plant bugs increases to 15 per 100 sweeps once the third week of squaring begins. However, consider using a reduced threshold of 8-10 plant bugs per 100 sweeps if square retention is less than 80%.
Adult Tarnished Plant Bug
I’ve neglected to mention a new product that was included in UT’s recommendations this year. Belay is a product from Valent. There has not been a lot of use of this product because it is new, and it costs more than some of the alternatives (especially the imidacloprid products). Belay belongs to the same class of chemistry (neonicotinoids) as Centric and imidacloprid. The active ingredient, clothianidin, is the same as that in Poncho (used as a corn and soybean insecticide seed treatment). Belay has pretty good activity on tarnished plant bugs. It should provide control similar to the imidacloprid products when used at a rate of 3-4 oz/acre. Like other neonicotinoids, UT recommends the use of Belay in cotton prior to flowering. The goal is to use the the neonic’s early and give them a rest once flowering begins to reduce the likelihood of developing resistance in populations of tarnished plant bug and aphids.
Adult Green Stink Bug
A number of people have commented about stink bugs in pre-flowering cotton, mostly the green stink bug. The presence of adults is of little concern until bolls are present, although it indicates that we have our fair share of stink bugs around this year. The neonicotinoids are not great at controlling stink bugs, but applications targeting plant bugs should winnow the population down. In my experience, Centric usually has more activity than imidacloprid.
2 thoughts on “Cotton IPM Update – Plant Bugs and Stink Bugs”
Your comments re/ imidacloprid performance on thrips and plant bugs suggest incepient resistance. (I know I’m using the ‘R’) word. In this situation would it not be preferable, i. e. more conservative, to use alternative products and give imidacloprid a rest. If we have incepient resistance and back off, we might be OK in 2012. If we push it with tank mixes we could kill imidacloprid off.
Bob
Resistance in thrips populations to imidacloprid (Gaucho) or thiamethoxam (Cruiser) is a possibility. However, I suspect it is not the case. I definitely have concerns that we could develop resistance to the neonicitinoid insecticides such as imidacloprid and Centric (thiamethoxam). These products are used heavily as seed treatments and prior to flowering. UT recommends avoiding the use of this chemistry in cotton (including premixes that contain neonic’s) once flowering begins in hopes of preventing or delaying resistance. We also try to avoid using OP and pyrethroid insecticides prior to bloom when possible, in part for resistance management and to avoid creating aphid or mite problems. We already know we have some level of resistance in plant bug populations to the OP and pyrehtroid insecticides. The good news is, in the little bit of screening we have done, we have not documented resistance in tarnished plant bugs to the neonic’s in TN. It is tempting to call control problems resistance, but sometimes it is just good old fashion pest pressure that gives the illusion of worse than normal control.
Your comments re/ imidacloprid performance on thrips and plant bugs suggest incepient resistance. (I know I’m using the ‘R’) word. In this situation would it not be preferable, i. e. more conservative, to use alternative products and give imidacloprid a rest. If we have incepient resistance and back off, we might be OK in 2012. If we push it with tank mixes we could kill imidacloprid off.
Bob
Resistance in thrips populations to imidacloprid (Gaucho) or thiamethoxam (Cruiser) is a possibility. However, I suspect it is not the case. I definitely have concerns that we could develop resistance to the neonicitinoid insecticides such as imidacloprid and Centric (thiamethoxam). These products are used heavily as seed treatments and prior to flowering. UT recommends avoiding the use of this chemistry in cotton (including premixes that contain neonic’s) once flowering begins in hopes of preventing or delaying resistance. We also try to avoid using OP and pyrethroid insecticides prior to bloom when possible, in part for resistance management and to avoid creating aphid or mite problems. We already know we have some level of resistance in plant bug populations to the OP and pyrehtroid insecticides. The good news is, in the little bit of screening we have done, we have not documented resistance in tarnished plant bugs to the neonic’s in TN. It is tempting to call control problems resistance, but sometimes it is just good old fashion pest pressure that gives the illusion of worse than normal control.