Alabama Insect Situation: August 12, 2023

We are beginning to see the “light at the end of the tunnel” for most of our late planted cotton across Alabama. We visited several fields in central and south Alabama this week and the crop looks good. Many fields in south Alabama were beginning to bloom out the top and are pretty much safe from bugs. There are still many fields at risk from plant bugs and stink bugs, however, so we can’t walk away yet.

Plant Bugs

Plant bugs are still heavy and requiring treatments in many later planted fields. For a lot of the crop however, its time to talk about plant bug insecticide termination. Recent research from the mid-south entomologists groups suggest cotton is “safe” from plant bugs once it reaches Node Above White Flower (NAWF) 2 or 3. Regardless of the plant bug populations in these fields, they are not doing economic damage and should not be sprayed. In our younger fields, plant bugs are absolutely doing damage and should be monitored and treated when threshold is reached.

Stink Bugs

Internal boll injury has made a big jump this week. On our research farms in Prattville, Headland and Belle Mina plots that had not been sprayed with a stink bug material had as high as 50% internal boll damage, even though we are not seeing that many stink bugs still. Similarly, in a ThryvOn demo plot we are sampling on a grower field in NE Alabama, we found 20% internal injury while averaging less than 2 stink bugs per 100 sweeps. This helps to make the point that we cannot be looking for stink bugs to make treatment decisions. Pull some 10–12-day old (quarter sized) bolls and look for damage. Peak bloom (weeks 3-6) is the most critical time to protect bolls and threshold is just 10%.

What to Spray for the “Bugs”

We have reached the point in the season in this late planted cotton, that we need to be thinking about both plant bugs and stink bugs when making insecticide decisions. That doesn’t leave us many options, just pyrethroids and organophosphates. Diamond will still have utility in some situations, but this late in the year, that will come down to a field-by-field decision. I have received several calls this week on “clean up” sprays of a pyrethroid plus acephate. This is a common treatment that does a good job killing most everything in the field and getting you through. There are likely some situations where plant bugs need something like Transform for control, I would advise adding a pyrethroid in the tank for stink bugs.

What about rates? At this point in the year, these plant bugs have been hit by just about everything. For pyrethroids and Bidrin, I would suggest running a 1:20 (6.4 oz) over a 1:25 (5.12 oz). The minimal savings on insecticide cost doesn’t out weigh the drop in efficacy. For Diamond, it may just depend on how much longer you need to go, but I am mostly recommending 6 oz still for most calls (if it is needed).

One other thought. As we reach the end of the year, try to get a final bug spray out before plants loaded up with bolls start to lean across the middles. In some cases, we may do more damage to bolls with the sprayer than stink bugs will do that late in the season.

Bollworms

We mentioned a few fields of Bollgard 2 requiring treatments last week and a few more have been sprayed this week too. The diamides (Besiege, Vantacor, Elevest) provide the best control, but are most effective on small worms or when timed with a hatch out. Pyrethroids MAY still provide some knockdown but scout behind them closely to make sure. Most of our fields are 3-gene (Bollgard 3, WideStrike 3 or TwinLink+) and we do not expect any issues with controls in those fields.

Soybeans

Things are still pretty quiet on the soybean side are still pretty quiet. We have heard of a few fields with low levels of loopers and velvetbean caterpillars but not at treatable levels. We have also started observing some stink bugs but not at damaging levels. Keep monitoring fields, at some point things will pick up.

Peanuts

Again, things are still quiet. Defoliating caterpillars are out there, but not at damaging levels. We have not heard of any spider mite problems yet, so avoid disruptive insecticide applications to avoid creating any issues.

As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501). For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.

Alabama Insect Situation: Friday August 4, 2023

The phone calls have picked up over the past week. Plant bugs have picked back up in some spots and in some areas of south Alabama they are still heavy. I spoke with one person in south Alabama yesterday about the insect situation in his area. He told me most folks are saying vigilant but getting frustrated with the number of plant bug applications going out. When asked about stink bugs, his response was “I think they all just morphed into plant bugs.” While that was a joke, it does bring up a point about stink bugs. We still just haven’t found many and still don’t understand why.

Plant Bugs

Plant bugs continue to dominate the situation, and a lot of calls have revolved around Diamond. This insect growth regulator helps to keep immature plant bug populations suppressed with good residual and rainfastness. Diamond is best used when applied at the first appearance of nymphs, but that doesn’t mean its ineffective at other times in the season. Right now, Diamond can still be a big help in keeping populations in check. We have received several calls this week about finding threshold populations of plant bugs 5 or 6 days after an application. Once we get embedded populations of plant bug nymphs, it can take up to 10 days to really see the effects of Diamond. That does not mean that I would not make a follow-up application in less than 10 days, but I would not reapply Diamond in less than 14 (6 oz) or 21 (9 oz) days.

Stink Bugs

Populations are still low, but we have reached thresholds of internal boll injury on the research farm in Prattville this week. Keep scouting and monitoring fields. If possible, try to get a stink bug material in the tank (Bidrin, Acephate, pyrethroids) when making plant bug sprays.

Spider Mites

We have received reports of spider mites requiring treatments in SE and Central Alabama this week. Reports from NE Alabama are that populations have held steady from last week and are bordering treatment levels in some fields. At this point in the season we have a few options (Portal, Zeal, Oberon) but abamectin (Agri-Mek and others) is the most economical option. There are two formulations of abamectin sold (0.15 and 0.7), regardless of the formulation, we should be on the higher end of the rate form this point forward. As cotton gets more growth, higher rates tend to provide better control.

Bollworm Flight

Our bollworm moth traps have picked up statewide in the past week. We have heard some reports of heavy egg lay and a few fields with escape worms requiring treatments in two-gene cotton. With the amount of VIP (3-gene) cotton we have now, we shouldn’t be too concerned with bollworms but we should be alert in the 2-gene varieties.

Soybeans and Peanuts

Calls for beans and peanuts are still far and few between. We have been alerted of soybean field at threshold for soybean loopers in the FL panhandle, but overall populations are just starting to build. Stink bugs have still not been high in most fields. Hopefully the early beans will get away without needing treatments. Later soybeans tend to be at higher risk so continue scouting and monitoring.

As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501). For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.

Alabama Crops Insect Situation: Thursday July 27, 2023

The plant bug situation has not changed over the past week. There are still some hotspots with high numbers of nymphs, but overall populations are manageable. We have also observed and received reports that adult plant bugs are showing back up in places, presumably moving in from nearby corn fields. When scouting, keep an eye out for borders with corn because that is likely to be where the highest pressure is. We have reached the point of the season where a sweep-net may be needed in addition to a drop cloth as nets are more efficient in picking up adults. Managing these populations of adult plant bugs is important because they will also be depositing eggs that will hatch out in the following 7-10 days. Keep scouting for plant bugs and be prepared to treat when needed.

Spider mites should be in the back of everyone’s mind right now. Spider mites have been reported at treatable levels in NE and SE Alabama this week, and we have observed populations in fields in central Alabama as well. The current long-range forecast doesn’t look favorable for soaking rains, which help beat spider mite populations back. At this point in the season, we recommend using higher rates of abamectin for controls. There are two formulations of abamectin sold (0.15EC and 0.7EC). Higher rates (12oz+ or 3oz) provide more consistent control in bigger cotton with a lot of canopy. Based on the current forecast, I could suggest being proactive on a spider mite infestation, particularly if going across the field anyway. Spider mite infestations are much easier to control before they “get out of hand.”

We have also heard about a few fields in south Alabama with escape worms in Bollgard 2 (BG2) cotton. We do not believe this is widespread, in other words, I wouldn’t start automatically treating all my BG2 fields, but we should be aware. Our threshold is when 5% small larvae (5 worms on 100 plants) or when 6% damage is observed (squares, flowers or bolls). There are several options for control, however they are all most effective when applied to small worms (>0.25”). We know there is some bollworm pyrethroid resistance, however, they may provide adequate control in some cases. The diamides (Besiege, Vantacor, Elevest) provide the best control, but at a price. If a pyrethroid is used, it should be monitored closely after application because the cost of a “miss” could be high.

Where are the stink bugs? That is one of the biggest questions we are getting right now. My answer is, I don’t know, but I hope they stay where ever they are. In general, there just hasn’t been a whole lot of stink bugs or damage observed in fields so far. It could be that we were more proactive in corn this year, or on plant bug management, or it could be related to weather somehow. Whatever the reason, we know the high damage potential stink bugs have and we need to continue scouting and be prepared to intervene when necessary.

Things have been very quiet on the soybean and peanut front. We have talked to a several folks this week and there doesn’t appear to be much action out there. There are some cloverworms in most fields, a few loopers and stink bugs here and there, but overall, not much. This highlights the importance of scouting and only treating when necessary. If there are no damaging levels of pests in the field, then there is no return on an insecticide application.

As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501). For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.

Alabama Cotton Insect Situation: Thursday July 20, 2023

Plant Bug Situation

Overall, we appear to be in good shape after the onslaught of adult plant bugs that infested fields in June. Phone calls have slowed down considerably, and most of the reports are that plant bugs are out there and in some fields at damaging levels, but manageable. I think we have two big factors that have helped us in this regard.

The first was our adult plant bug management. As we have talked about a lot this year, our recommendation in Alabama is to treat a threshold population of adult plant bugs, regardless of square retention. We believe this helps to preserve square loss before it happens and reduces egg lay. The immature populations in fields now are a result of this egg lay in June. Allowing a threshold population of adults to “ride” a week to wait for square loss gives them the chance to lay tens of thousands of eggs per acre over the following 7 days. Killing these adults before they have the chance to feed and lay eggs has helped keep populations manageable.

The second thing that has helped us to this point is the use of Diamond. When timed properly, Diamond provides residual suppression of plant bug nymphs. While not in all cases, reports we have received seem to indicate that following an application of Diamond + a knockdown insecticide, many fields have bought themselves to the stink bug window (≈3^rd week of bloom).

Stink Bug Situation

Speaking of stink bugs, reports of populations and damage in fields are trickling in. Remember our threshold changes by week of bloom. Early bloom (weeks 1-2), threshold is 50-30% boll damage. Peak bloom (weeks 3-6), threshold is 10% boll damage. Late bloom (weeks 7-8), threshold is 30-50% boll damage. Right now, reports are that most of the populations are brown stink bugs. Typically, the green species show up towards the end of July or first of August. In general, pyrethroids aren’t as good on browns as organophosphates (Bidrin, acephate). However, pyrethroids often do a good enough job on browns to keep populations below threshold. Also consider your plant bug situation and resistance levels if needed to make a bug complex spray.

Others

We have received several calls on aphids over the past week. In most fields, populations are heavy in localized areas and are not a concern for treatment. We don’t often recommend treating aphids, but some situations may require an application, such as if cotton is drought stressed and/or late or if populations are making scouting other insects, like plant bugs difficult. We have gotten a report of the fungus killing aphids in the Wiregrass, so we should expect populations to start crashing soon.

We have some pockets of spider mites in fields but overall we have not gotten too many calls lately. Watch the weather and behind applications of broad-spectrum insecticides for mites building.

We observed some bollworm egg lay in fields in central Alabama this week, but we have not heard of any escapes in two or three-gene cotton.

Update on ThryvOn

I also wanted to give a quick update on some of the calls we are getting with ThryvOn. ThryvOn provided excellent control of thrips in every field we visited and based on all the feedback we received during the thrips window. In June, when adults were migrating in, it was hard to see what ThryvOn was doing. In many fields, populations were above threshold and square retention was dropping. Some folks were frustrated with having to treat these fields since it has a “plant bug trait.” However, we are now starting to realize some of the benefits. We have gotten calls across the state reporting that non-ThryvOn fields with similar planting dates and pre-bloom insecticide regimes are being treated for immature plant bugs, while they cannot find many nymphs or dirty bloom in the ThryvOn. This is what we hoped to get from this technology in Alabama, “saving” a spray in July and pushing us to the stink bug window.

Final Thoughts

We are off to a good start, but still have a long way to go. Keep scouting and monitoring fields and be prepared to make timely applications when needed. As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501).

For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.

Alabama Cotton Insect Situation: June 29, 2023: Plant Bugs Continue to Build

The plant bug situation has continued to increase over the past week. Going back at least 51 seasons, this appears to be the most widespread and highest pressure we have seen in Alabama. There are fields with numbers as high as 5x threshold in some places. Many fields have received 2 pre-bloom applications, and some have had three.

The question is “what do we do?”

In a lot of these fields, plant bugs are reinfesting so fast, 7–10-day spray windows are not holding up. Remember that no product provides residual control of migrating adult plant bugs. We may expect 48-72 hours of control, but past that, things get dicey. In other cases, the number of adults in the field is hard to get under control with our “normal” plant bug regime.

In most years, the highest labeled rate of imidacloprid is “good enough” to get populations under threshold, persevere square retention and reduce egg lay. In many fields this year, the ≈60% control we get leaves numbers out there that we can’t live with. In other words, 60% of 8 bugs/100 sweeps is 4.8 bugs in the field (below threshold), while 60% of 12 bugs/100 sweeps leaves 7.2 bugs in the field (right at threshold). Again, in high pressure fields, the highest rate of imidacloprid alone will likely not keep populations in check.

What about pyrethroids? We have a graduate student, TJ Douglas, who has been screen adult plant bug populations for resistance to several classes of insecticides this spring. In his preliminary analysis, he has found HIGH levels of resistance to bifenthrin in the TN Valley (Limestone County, we have known this for years), SW Alabama (Monroe County), and East Central Alabama (Elmore County). A population from the SE Alabama (Henry County) came back with elevated levels of resistance (but ≈62% lower than SW Alabama). Populations in NW (Cherokee County) and West Central (Dallas County) came back much easier to control.

What does this mean for 2023 in regions with resistance?

We have known about pyrethroid resistance in the TN Valley; thus, they have not been recommended for control for years. Over the past 2 seasons, we began receiving scattered field complaints in SW Alabama. Due to these experiences and results from lab tests, we are no longer recommending pyrethroids in SW Alabama for plant bug control. We have not received field complaints from the Wiregrass or East Central Alabama following pyrethroids, so this resistance could be “pocketed” and not widespread across the region. It is hard to say what we will get out of pyrethroids in these regions this year. Choosing a pyrethroid for plant bug controls may come down to a grower-by-grower decision based on their experiences. I would be very cautious using a pyrethroid in the Wiregrass and EC Alabama and scout closely behind to monitor performance.

What does this mean for 2023 in regions with no resistance?

In NW Alabama and the Black Belt, we are still comfortable recommending pyrethroids for control of adult and immature plant bugs.

So, if imidacloprid isn’t good enough and pyrethroids are resistant, what are we going to do with adult plant bugs?

Centric (thiamethoxam) is still an option. Centric is a neonicotinoid (like imidacloprid), just a little more expensive. Centric at 2 oz/A has always been better on adult plant bugs than imidacloprid and resistance monitoring suggests populations are still susceptible across the state. **Note: Centric often does not provide adequate control of immature plant bugs.

Acephate is another good option for control of adult plant bugs. The ½ lb rate of acephate should provide adequate control. In some fields, acephate plus imidacloprid has been used with positive results. Resistant monitoring shows that plant bugs are still susceptible statewide. **Note: Acephate is often associated with spider mite outbreaks in days or weeks following application.

Transform is probably the best plant bug material currently on the market. We typically like to hold the “big gun” until bloom, when immature plant bugs begin to emerge. The 1.5 oz rate of Transform provides good control of all stages of plant bugs, but at a price. This product is important for controlling immature plant bugs.

What about tank-mixing imidacloprid and bifenthrin? We have some data on this from the TN Valley on immature plant bugs. In 2021, it provided pretty good control. In 2022, it did not provide any measurable level of control. This mix may work on migrating adults, but it may be a total miss.

**Bidrin is restricted by label until bloom and cannot be used in the pre-bloom window**

How do I know if my insecticide worked?

While still important, monitoring adult populations in the field following an application is not the best way to determine if the most recent application work. Adults may reinfest fields and it is not uncommon to find as many or more adults in a field 5-7 days after a spray than before. The best way to determine the efficacy of an insecticide application for adult plant bugs is to monitor pinhead square retention 4-5 days later. If retention falls 10% or more 4 days later, then it is likely that either the application did not work or could not perform under the pressure. Use this information to guide follow up applications. If retention is holding (and greater than 85%) but threshold levels of adults are in the field, then a follow-up application is still warranted.

What about cotton with immatures present?

In a lot of the older cotton in Alabama, immature (nymph) plant bugs are beginning to or have been emerging over the past week. In this situation, where adults are still migrating in and nymphs are showing up, Diamond is critical for control. We wrote a lot about using Diamond last week (link), but here are a few reminders: Diamond is not a “knockdown” insecticide and should be tank-mixed with one. Diamond provides residual suppression and does not eliminate plant bugs or the need for follow up applications. Think of Diamond like ThryvOn: populations can still build to damaging levels but are lower than they would be if not used.

After bloom, acephate, Transform and Bidrin are options to consider tank-mixing with Diamond.

Getting off to a good start in this cotton with nymphs emerging will be critical to “set the tone” for the rest of the season.

As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501).

For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.

Alabama Cotton Insect Situation: Friday June 23, 2023: Plant Bug Pressure on the Rise

We have received reports of threshold populations of plant bugs from the Gulf to the Tennessee line and from Mississippi to Georgia. If cotton has squares, it should be scouted for adult plant bugs. In Alabama, our threshold is 8 adults per 100 sweeps -OR- to maintain 80% square retention. Some states recommend only treating adult plant bugs if square retention falls below 80%, regardless of the number of adult plant bugs in the field. We have a couple of reasons for treating 8/100, regardless of square retention.

1.       A square will likely not fall off the plant the day it is fed on by a plant bug. In other words, you can find a field with high plant bug numbers and high square retention because plant bugs have moved in recently and fed on squares, but they have not had enough time to fall.

2.       Consider the damage potential of plant bugs. A threshold level would result in unacceptable square loss in the following week. The literature says that adult plant bugs feed on 0.6 to 2.1 squares per day. A threshold population of adult plant bugs is ≈1,160 bugs per acre. Assuming a plant population of 36,000 plants per acre and an average of 2 pinhead squares added each week, then a weeklong infestation of a threshold of adult plant bugs will result in up to of 17,052 squares lost, or ≈24% of the pinhead squares in the field. If we know that damage potential is possible, don’t wait for it to happen.

3.       In addition to feeding on pinhead squares, adult plant bugs also lay eggs. These eggs will hatch out over the following 7-10 days, resulting in an embedded population of immature (nymphs) causing problems later in the season.

Speaking of egg lay and plant bug nymphs hatching out, this brings up the timing of the insect growth regulator, Diamond. This chemical is only active on nymphs and kills them as they molt (shed skin) and grow from one instar (growth stage) to the next. Immature plant bugs develop through 5 instars over ≈15 days. As mentioned above, the egg stage lasts 7-10 days. This makes the timing of Diamond critical to maximize its effectiveness. We feel that we get ≈2 weeks (TPB nymphal life length) of residual suppression from a 6oz rate of Diamond. Timing this application as close to the initial hatch out as possible helps to get the most “bang for your buck” out of this.

Typically, we say that around 1^st bloom is the best time to apply Diamond. This assumes that a threshold population of adults in June was present in the field and killed with a well-timed spray when found. In a “normal” year, adults move into fields when 3 or 4 pinhead squares are present (≈2 weeks into squaring). Given time for eggs to deposit and nymphs to hatch out, we typically expect to start finding nymphs around 1^st bloom. This year in many fields, adult plant bugs were found in fields with 1 or 2 pinhead squares present (≈1^st week of square). Additionally, there are a lot of fields that had a threshold (or higher) level of plant bugs for 7 or more days before an application could be made due to rain. In these cases, Diamond should be applied earlier than the 1^st week of bloom. The point of this application is not to time up with crop stage, but with plant bug nymph emergence.

Bottom line: In many of the phone conversations we have had with folks this week, we are telling them that if high plant bug populations are in fields and no adulticide has been sprayed, then Diamond should be applied (with a knockdown insecticide) 10-14 days after the initial threshold population was observed. Making a Diamond application does not mean plant bug numbers will not reach threshold in the following 2 weeks, but it will help to keep numbers suppressed, especially if rains or other factors will not allow for timely follow-up applications.

As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501).

For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.

Alabama Cotton Insect Situation (And Thoughts on Plant Bugs): Thursday June 15, 2023

Plant bugs are on the move. We have heard reports of adult plant bugs moving into fields across Alabama. A lot of fields in SW Alabama and some fields in Central Alabama have been treated over the past couple of days. The rain much of the state is experiencing will likely keep scouts and sprayers out of the field for a few days, but we need to get back in there as soon as we can. Until this week, we had been pretty dry in some parts of the state. The daisy fleabane has begun to play out and plant bugs are looking for better hosts. In most cases, that will be the oldest cotton around. In other areas, we have received timely rainfall and/or soils seem to be holding water better, leaving more fleabane in the environment. In these areas, plant bugs have started moving, but we will likely have another migration as the next generation matures our in a couple of weeks. We have also heard about spider mites and three-cornered alfalfa hoppers in some areas, but plant bugs are the biggest reports we have received.

I also wanted to put in plug from a post by Dr. Camp Hand at UGA discussing hail damage in cotton. I am not sure exactly how much we have in Alabama, but I suspect there are some fields suffering from it. You can read his post here (link).

Managing Plant Bugs Following the Storms

I had a discussion with a consultant this afternoon in central Alabama, and he brought up a good point to consider. He had a couple of fields with plant bug numbers close, but just under threshold earlier this week. Thinking the rain would cause some wash off (which it certainly would have), he and the grower decided to wait until the storm passed to treat. Now, assuming no more rain comes, they will likely be out of the field at least a week, potentially longer if rains continue. Plant bugs will be in the field depositing eggs over a 10–14-day period, meaning immature plant bugs will likely begin hatching around June 20^th and continue through the first of July. His question was basically, is it time for Diamond as soon as we can get the sprayer in the field. In this situation, the answer is probably “yes.” If they can get into the field around June 22^nd, that gives us good timing for the initial hatch out (around the 20^th) and we will expect to get 2-3 weeks of residual immature plant bug suppression from the 6-9 oz rate.

Remember Diamond should be tank-mixed with a knockdown insecticide to kill any adults in the field or immatures that have already hatched. Diamond kills immature plant bugs when they molt from one instar (growth stage) to the next. Plant bugs go through 5 instars with most of the damage being done in the 3^rd-5^th instar stages. This is why the timing of a Diamond application is so important. If the treatment is made too early, then some of the residual is wasted. If the treatment is made too late, plant bugs in the field will continue to feed and cause injury until they molt to the next instar.

We normally do not recommend Diamond being applied until nymphs begin to emerge, typically around first bloom (or the first of July). However, that is considering an application went out for migrating adults in the pre-square stage (mid-June). Others may have this unique situation where they know plant bugs are in the field, but they cannot do anything about it for a week or more. In these situations, I would suggest a Diamond application be made when a treatment goes out. If the ground dries out quicker, or a plane is available, I would suggest going ahead and treating threshold levels of plant bugs (8 bugs/100 sweeps or 80% square retention) now and waiting to make a decision on Diamond around the first of July.

As always, if we can ever be of any help, or if you would like to provide input on the situation in your area, please don’t hesitate to reach out (Scott Graham: 662-809-3368; Ron Smith: 334-332-9501).

For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter, and the Syngenta Pest Patrol Hotline.