 Hello, my name is Tim Reed and I'm an extension of Modest with Auburn University. Today I want to talk about scouting for insect pests of cotton. If we look at the different insect pests that tend to be issues in cotton or have historically been issues in cotton over the last few years, we see that the first pests that show up in cotton are cut worms and and then thrips followed by aphids and spider bites potentially. Sometimes aphids and spider bites develop good populations in cotton because of its outside applications made for thrips control. Then once cotton begins to square, we start seeing plant bugs moving in the cotton field and start feeding on squares. We have, after the cotton begins to bloom, we can start to see bow worms and then when cotton sets bows we'll see stink bugs and in the past we have had issues with fall army worms. They have not been as serious a problem in recent years as they once were with the BT cotton and then lastly we can see why fly problems develop in the cotton fields. With cut worms, these are greasy large worms that crawl around beneath the soil surface or under the soil plant residue that is left from weeds or the previous crop. They feed on the stems and the leaves. There are at least four cut worm species in Alabama, the army cut worm, the granulated cut worm, the black cut worm, and the variegated cut worm. They all have a little bit of different feeding preference in the way they attack cotton but they're all, this black cut worm here on the black belt soil is underneath some corn residue. What we see here is the kind of symptoms you may notice in the field when you've got cut worm damage. They will sometimes cut off the stem and pull the plant down in their hole and feed on it. Sometimes they'll feed on the cotyledon leaves and damage the plant. This is cut worm feeding damage to corn so you can see kind of how the feeding may look. You manage cut worms by applying a pyrethoid at planting. Growers should always apply a pyrethoid when planting into pasture grasses. However, the cut worms can also show up in fields that were planted to peanuts or cotton the previous year in corn. Cut worms are more difficult to control when cotton is planted into a heavy residue left by a previous crop and therefore you may have to spray twice with a pyrethroid if you're starting to see stand loss after the cotton plants emerge. Light to moderate cut worm problems can be serious if the stand of plants is on the thin side to begin with. Cut worms can slow to reduce the cotton stand over a two to three week period and growers should be checking the seedling plants regularly for cut worms. Another occasional pest of cotton seedlings is the vegetable weevil. This insect is extremely small as you can see here where it's being pointed at with an end of a knife. It feeds on the leaves and stems of seedling cotton. Damage can resemble cut worm injury and you may have to dig around the plants to find them. You can also sometimes find vegetable weevils associated with weeds such as cut leaf evening primrose. Here's an example of a clipped plant that a vegetable weevil fed upon. You also have feeding on seedling cotton plants by slugs and snails. Slug feeding damage is shown here. It looks a little bit like the damage you see on soybeans by bean leaf beetles with respect to the holes you may see on the plants. Very difficult to control and expensive. You have to use baits and a lot of times farmers where they have real serious issues will just have to replant after they have slug damage. Also the slugs can feed on the stem of the plant. This is a soybean plant that was thought to have slug damage because we did have a lot of slugs in the field that were feeding on the leaves. Foschenschberg can also be a pest of cotton especially in droughty conditions. Here we see a plant that's been sucked down by large numbers of Foschenschbergs during a dry period. The Burr bug has been an issue on occasion in Alabama. This insect will move to cotton plants if you don't have an insecticide seed treatment on it they can suck the cotton plant down as well. Grasshoppers were a problem this year on seedling cotton in Central and South Alabama especially. The immature stage is fairly easy to control with a pyrethroid. Once they get wings you have to use a pretty good rate of orthane to control them. They'll feed on the stems and on the leaves. They like to feed on the crook stage. When the cotton first comes out of the ground they'll clip them off right below the cotyledons and can do a significant amount of damage especially around the edge of the field. Here you see an adult grasshopper that has been feeding on the cotyledon leaves at these seedling soybean plants. Thrips are one of the most serious pests of cotton from an economic standpoint in terms of the amount of money we spend to control them each year with preventative treatments plus foliar sprays that we often have to apply. The tobacco thrips is the primary species that is a pest of cotton. It usually constitutes 90% or more of the total thrips populations infesting cotton two to three weeks after emergence. They generally rank right behind plant bugs in terms of the amount of economic loss in North Alabama and in South Alabama they'll rank behind stink bugs in terms of the pests that cause the most economic loss. Here's some of our thrips plots from 2017. You see the untreated plots. There's four rows of untreated plots to my left and then there's four rows of treated plots on the right with the insecticide seed treatment that was a combination thymothoxanomidic local treatment. These plots were planted on April the 14th. Plots that were planted on April the 20th also sustained significant thrips damage especially the untreated plants. When we're looking at the thrips damage to cotton we rate the damage based on the level of feeding that we see on the cotton seedlings the first true leaf and then the subsequent true leaves that appear usually through the fourth true leaf stage cotton is susceptible to to yield loss from thrips feeding. The plant on the left the damage level would be rated a four. The plant on the right would be a zero since we see no damage. If you have no damage and no thrips present the rating is zero. Here's another slide that shows the damage rating scale we use of zero to five and this is not a perfect set of pictures but it does give you an idea of what types of damage we we might look at and rate them at a certain level particularly I want you to concentrate on number three. This is the level of damage that one might want to give serious consideration for making a thrips foliar application. When you see two true leaves on the plant and there's a lot of disfigurement of the true leaves and thrips are present and then on number five is what you may run into shortly thereafter if you don't treat it thrips but continue to move into the cotton field where they will kill the bud the plant the plant will sometimes die. The faster cotton can grow off after developing the first true leaf the less likely it is to have serious damage by thrips. The best time to spray cotton is at the first true leaf stage when thrips are attacking cotton and research done by Alana Jacobson has shown that the eggs of thrips are laid primarily on the cotyledon leaves. You can flare aphids and spider mice with thrips insecticide sprays. Last year we we've flared spider mice with two seedling sprays of orthoine at the pravil station. Sometimes insecticide seed treatments are not uniformly applied to seed this is very common and there can be some plants with damage symptoms and others without damage. In this situation a North Carolina recommends treatment when there are two thrips for planting 25 percent of the plants are damaged. This is a slide from Phillip Robertson's Tifted Georgia where he looked at the long-term effects efficacy of neonicanoid seed treatments compared with timic or aldecarb. This is a combination average of 20 trials and he found that two weeks after planting he was getting 60 percent control with his seed treatment versus 80 percent with timic in three weeks after planting it drops down to 40 percent and we normally assume we'd get two to three weeks of efficacy of a neonicanoid seed treatment on cotton and this is from the day it's planted not from the day of emergence so if you're planting dry conditions and the cotton plant doesn't come up then for two weeks then you'll probably will see some significant thrips damage on cotton that's planted before May the 5th in North Alabama and maybe May the 1st in South Alabama but that can vary from year to year depending on the weather and planting insecticides must be taken up by the roots and translocated to the growing point to provide effective thrips control. This water solubility that is required for insecticides to work also allows leaching of insecticides out of the root zone when rainfall is heavy thus the insecticide treatment becomes less effective. I also need to mention that the good entomologist over at Mississippi State are reporting they're getting about another week's residual activity out of inferus sprays versus neonicanoid seed treatments. Last year at Balvina we had fairly decent damage from thrips in our research plots the yield range for insecticide treatments was about 4,200 about 4,000 pounds of seed cotton per acre there were nine insecticide treatments some were foliar some were seed treatments some were a combination of both. All had a crop residue which tends to reduce thrips damage the average for all those nine insecticide treatments which would be 36 plots was just over 4,000 pounds of seed cotton the untreated plots which there were 12 had a yield average of 3725 pounds and then at economic consequences of using those seed treatments was about a hundred dollars per acre of value of value minus the cost of the seed treatment. If you're planting into a thick cover crop stubble this will reduce thrips damage in comparison to planting into a conventionally till field. As I mentioned earlier sometimes you can flare insects behind thrips sprays including aphids aphids will attack cotton once from the time it comes up until it's starting to mature they feed on the underside of the leaves they have a tremendous reproductive capacity and the nymphs are born with developing embryos already present in other words they're born pregnant one female can produce as many as 80 young individuals that mature within eight to ten days so aphids possibly could have as many as 50 generations per year and they occur as frequently as every five or seven days some of the aphids are weaned and some are not weaned they tend to really make a mess on the plants but when they start they tend to really make a mess on the plants when they start to get large populations and they shed their skins and it's hard to scout the cotton terminal especially for other insect issues when you have aphid problems leaves will start to curl up like we see here turn downward when you get a lot of aphids on the underside of the leaves you'll get honeydew on the from the aphids feeding on the leaves above the little drop down on the leaves below on the surface of the leaves below make a sticky mess and then a sooty mow will develop on those cotton leaves where the honeydew was deposited and this can cause us to have a serious price reduction or cotton because of a reduction in grade from the sooty mow predators parasitoids and aphid killing fungi are often the most effective means of managing an aphid population the aphid killing fungus usually appears by mid-july but sometimes the fungus doesn't reduce the population until over into august and this is generally the case when you have extremely dry conditions farmers tend to want to wait before they make a spray for aphids but sometimes you have to apply insecticide to reduce aphid populations to avoid a yield loss aphids scale insects and white flies are often tended to by fire ants that that want the honeydew that the aphids are secreting when aphids are on cotton plants research done at Auburn University in the early 2000s indicated that the fire ants became more abundant on the foliage as a consequence of the aphids being present there when the fire ants are more abundant on the foliage they alter the the number of caterpillars and beneficial insects that are also on the the foliage they tend to reduce the those numbers more so it's a very interesting mutualistic relationship between fire ants and aphids and how they impact the populations of other insects on the cotton plant spider mites as we mentioned earlier can be an issue in cotton pretty much season long this is an adult along with some eggs you see here the spider mites feed on the undersides of the leaves they will abrade the leaves and they will the raspy sucky mouth parts and they will imbibe the fluid that comes out of the leaf we've observed in alabama that if we we could control spider mice with bifenthrin but bifenthrin kills the predacious thrips that feed on the spider mite eggs and will seal resurgence quite often behind bifenthrin's applications for spider mite control but we still could use bifenthrin for spider mites later on in late in late season when there's not a lot of time left for the crop matures when for spider mites feed on leaves they'll leave these uh initially this yalla stippling effect as the damage starts to show up on the leaf surface from the speeding on the underside of the leaf later on the leaves will turn a redder color like we see here um tarnished plant bugs once cotton begins to square are a significant pest of cotton in alabama especially north alabama the queen islace is another excellent host for tarnished plant bugs the immature stage will show up in the cotton plant later on in the year in july if we let a lot of eggs go meet the posture of the cotton plant uh during the early part of the squaring period then later on when the cotton gets ranked we may have problems getting the insecticide down into the plant and controlling these immature insects tarnished plant bugs will feed on the the fruit of the cotton plant they will inject a toxin that will dissolve the tissue in the square so that they can suck it out and feed on it and then the square will turn brown and fall off excessively heavy feeding on the cotton plant by the tarnished plant bug and resulted in crazy cotton where the plant loses apical dominance as the plant bugs move to the growing point of the cotton plant after they've knocked off all the squares and you see a plant that is abnormal in shape and has very little fruit on it tarnished plant bugs can feed on the bones squares before they open up and sometimes they will defecate at the top of the square they'll feed through the through that square prior to bloom and they can damage the reproductive parts of the plant they can feed on those reproductive parts after the bloom opens up Barry Freeman a professor emeritus at Auburn University did a lot of research trying to quantify and just demonstrate a relationship between bloom damage and by plant bugs and yield and he was never able to develop a correlation there was no positive correlation between those two variables also we have the clowny plant bug that has the antenna forked at right angles as we see here and in this slide they tend to show up later in the year most years but sometimes you can find a few of those in the first part of July and cotton fields sometimes it's very hard to distinguish damage between tarnished plant bugs and stink bugs but they will all feed on bowls and I can't say for sure that this is tarnished plant bug damage but it is normally a problem with tarnished plant bugs that will feed on smaller bowls earlier in the year and as we go on into the growing season they can continue to feed on bowls but they they tend to not do as much damage as stink bugs in terms of the amount of damage done internally to the bowl here we see the green stink bug adult immature which tends to be more of a problem on cotton in north alabama while the southern green stink bug is more of an issue in central and south alabama this is the adult and this is the immature southern green stink bug we also have a brown stink bug this is the use use just a service species and this is the immature stage of the brown stink bug brown marmorated stink bug is moving into alabama becoming established in more and more counties we have a significant population at the practical agricultural research unit in central alabama and this insect will feed on a larger bowl than than the native species of stink bugs that we have normally what happens with cotton is that about the third week of bloom we have bowls in the field that are eight to ten days old these bowls have a seed beginning to develop and the stink bug wants to feed on the seed where the protein level is highest so it will insert its proboscis into the seed feed on the cotton plant it'll cause these abnormal growths on the inside of the bowl wall and it will cause the internal portion of the cotton plant to to rot here we see some locks of cotton of a cotton bowl that have been damaged by the stink bug and it's a very sad thing to go out into a grower's field he doesn't realize he's had any damage because the bowls are still there he didn't pull bowls and check them during the growing season and he ends up with a situation like this so the treatment threshold for stink bugs changes as we get into the blooming period but peat bloom or damage is about threshold is 10 percent punctured bowls the stink bug trapped my threshold for cotton as i mentioned is 10 to 15 percent bowl injury during the third to fifth week of bloom when the highest number of septic bowls are present use a 20 percent injury threshold for weeks two and six of bloom the cotton bowlworm and tobacco budworm have historically been significant pests of cotton whether the introduction of bt cotton however we have seen the significance of these pests decline bowlworm and budworm mostly shiny eggs pearly pearl shaped eggs on the cotton plant these will hatch in about three days under hot weather conditions and we see here on the left a bowlworm egg on the left and on the right the egg of the predator the big eyed bug and this is a big eyed bug adult uh we normally look for bowlworms in the terminal of the cotton plant especially prior to the bloom stage uh and then on we still we move our search down the plant to the blooms and underneath the leaves around the bowl as we get on into the growing season the worm will feed into the bowl and move on into the bowl and eat the inside of the bowl causing significant yield losses with respect to bowlworms we need to remember that the white-striped cotton varieties or varieties in alabama that we tend to see some damage from bowlworms but this could be managed by pyrethroid applications historically we've been able to kill bowlworms with pyrethroids in cotton alabama these applications need to be made around august the first in north alabama and central alabama around june the 20th and then in south alabama as early as due to the tense since the bowlworm population tends to increase from south to north over time the last pest we'll talk about will be the bandied wing white fly historically this was a pest that showed up in cotton fields that received a large number of insecticide applications um however sometimes these pests just show up in cotton fields in other parts of the southeast they don't necessarily have to be flared by insecticide sprays they can be especially abundant and look like snowflakes falling in the air in the south georgia at times especially in the tifton area and these insects lay eggs on the underside of the leaves the crawler stage will find a place to become established on the underside of the leaf and it will go through several instars and moat and it would it can produce honey do just like aphids can do i want to thank everybody for their attention i hope the this program was a benefit to you and if you have any questions you can call me at the alabama property safety system albert university thank you very much bye