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Friday, June 23, 2017

South-West Plains IPM Update Volume 17, Issue 7

GENERAL CONDITIONS:

Cotton in general is doing good giving the weather conditions over the last 7 to 10 days. Cotton in the area is ranging from just emerging up to pinhead squares. We have not found any insect pest in our cotton fields, but are starting to see a few more beneficials move into fields. These are mostly hooded beetles and crab spiders. Fertilizer applications, weed management, and managing growth using Plant Growth Regulators (PGRs) is what we need to be focused on for the next week to two weeks, especially if the rain chances materialize over the weekend.

Peanuts are growing good, but with this hot weather water consumption has increased. All fields in the scouting program started blooming this week, and has increased the water demand for the crop. Diseases have not been found yet, but there are still white grubs and wireworms being found in fields. Nitrogen applications in fields low on root nodules and preparing sprayer and/or chemigation systems are what should be focused on in the coming days.

A much need cool down is forecasted for this weekend and into early next week, as a cool front move through the area. Temperatures are expected to be in the 70s for daytime highs and in the 60s for nighttime to early morning lows. We are also getting a much-needed chance of rain starting this afternoon, as I am finishing this newsletter, parts of Gaines and Yoakum Counties are receiving showers. This rain will help our dryland crop progress, as it is limping along waiting for much needed moisture, and will help prevent drought stress in our irrigated crop which could cause square loss in cotton and poor pollination and pegging in peanuts, let’s just hope these storms are not accompanied by hail, and high winds.

COTTON:

Cotton is ranging from 2-true leaves up to 8 -true leaves, and pinhead squares are starting to form. This week squares were found in half of the scouting programs fields, and the first fruiting branch is between node 5 and node 7, with a 100 percent square retention. This variability in growth stage puts us in a situation where we are still checking for thrips in some fields, while in others we are moving to check for fleahopper and other plant bugs. Over the course of the last seven days, no fleahoppers have been found, but I would like to talk about identification and economic thresholds for fleahoppers in this newsletter to give you an idea of what we need to be looking for. Cotton fleahopper are pale green in color and are about 1/8th of an inch long. Their body is flat and elongated with an oval outline. On the back of the adults there are minute black hairs and spots. Nymphs of the cotton fleahopper appear the same as the adults, but without wings, however, initially are white in color until they feed. Once a Nymph has fed their color will turn to pale green with reddish eyes. Cotton fleahoppers have numerous wild host which they can overwinter on, these include silver leaf nightshade, woolly croton, and horsemint to name a few. Cotton fleahoppers use their piercing sucking mouthparts to remove plant sap from the tender portions of the plant. Square that are smaller than pinhead size is most susceptible to fleahopper damage, and square feeding can cause the square to die, and turn brown. Economic thresholds for fleahopper in our area is based on the number of insects per 100 terminals, and the percent of square set (Table 1). Treatment for fleahoppers is rarely justified after the 3rd week of squaring, because at that time we should be blooming and at this point cotton is typically able to compensate for some square loss. Last year Kerry Siders, Extension Agent-IPM for Hockley Cochran and Lamb Counties and Dr. Pat Porter, Extension Entomologist in Lubbock produced an excellent YouTube video covering the fundamental of scouting for fleahoppers on the Texas High Plains, it can be found at https://www.youtube.com/watch?v=epVctkRkTHs. Additional information of biology and chemicals that effectively manage fleahopper populations can be found at http://cottonbugs.tamu.edu/fruit-feeding-pests/cotton-fleahopper/.






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PEANUTS:

Peanuts are faring well for the recent hot and dry spell we have been in, and all the peanut fields began blooming this week, with one field starting to show peg development. This is time where we need to be applying our nitrogen to fields that are lacking in root nodules. Over the last two week the field scouts and I have been taking nodule counts, and most of the fields are averaging less than 10 nodules per plant. This low nodulation could be because of the roller coaster of a weather pattern we have been on the last 6-8 weeks, lack of putting inoculant down, or even inadequate storage of inoculants. With most of the fields having below 10 nodules per plant, these fields will benefit from a nitrogen application, and fields that have less than 6 nodules will need Nitrogen applications.

Diseases have yet to be found in the scouting program’s fields, and we are getting to the time where a shot of a fungicide such as Azoxystrobin (Abound) can be used as a preventative. Timing of this application typically occurs between 60 and 90 days after planting. When getting ready to apply we want to make sure we are starting to set pegs, as this will allow you to maximize the amount of fungicide in the active pod development zone of the soil. Knowing what pod rot pathogens are present in your field can help you to effectively manage this disease by selecting the correct fungicide, as not all fungicide effectively manages both pod rot pathogens. Azoxystrobin the active ingredient of Abound, Artisan, and Convoy for example is active against Rhizoctonia, but is only known to suppress Pythium pod rot, at the maximum labeled rate of 24.5 oz/acre. Pythium pod rot on the other hand can be effectively managed by using Ridomil, which has numerous formulations such as liquid and granular. The last thing to consider is application method. These products work extremely well when applied using a chemigation system, but can lead to bare soil being treated. Application cost can be reduced when these products are banded over the effect pegging and pod development zone, but it is best to increase the carrier volume to a minimum of 20 gallons as some fungicides are such as Ridomil formulations bind to the surface of leaves rather quickly. Irrigating shortly after application can also increase the amount of fungicide that reaches the pod development zone.





Thank you to all the sponsors of the South-West Plains IPM Program. The sponsors of the program for the 2017 growing season are below.

Platinum Sponsors:

Gold Sponsors:
Doyle Fincher Farm
Golden Peanuts and Tree Nuts

Silver Sponsors: 
Birdsong Peanuts

Bronze Sponsors:
Crop Production Services
New-Tex Gin, Inc. 




Sunday, June 18, 2017

South-West Plain IPM Update Volume 17, Issue 6

GENERAL CONDITIONS:
                 Hot, dry, and wind has been the story of the last 7-10 days, and this weather pattern that we are in has been harsh to crops in Gaines, Terry, and Yoakum Counties. This weather has negatively affected our cotton from getting a stand. Cotton in the scouting program is ranging from just emerging to the 4-true leaf stage. Thrips are still present in local cotton and peanut fields, but none of the fields in the scouting program have reached threshold. Earlier this week we were seeing wind damage to young cotton plants that was mimicking thrips damage, more on this will be in the cotton section of this newsletter. Some areas in Terry County this week received some rain, however, like any storm around this time of year high winds and hail accompanied it. There are reports of fields being lost due to hail damage around the FM211 and FM168 intersection. I am not aware of how wide spread this damage is, but it does not appear to be South of Highway 380 and West of Highway 385, as I drove around trying to see the extent of the damage.
Peanuts are starting to bloom, and if you have not evaluated your field(s) inoculation program, now is the time. Evaluating our nodulation on a field by field basis helps to determine which fields could benefit from mid-season Nitrogen applications. We have not observed diseases in peanuts yet this year, but soil inhabiting insects, such as wireworms and grub worms are being found more often.

COTTON:
Thrips are still a concern for most of the cotton fields in the area, but are still staying below threshold. Thrips are only an economic pest until the 5-true leaf or once the plant begins to square. At our current situation, our irrigated cotton will reach this stage in a very short time. Cotton need between 50 and 60 Growing Degree Day 60 (DD60s) to emerge after planting, and need another 425 to 475 DD60s to reach squaring. Based on the DD60s below (Table 1), cotton planted before May 10th, bearing inadequate weather conditions should be squaring within the next 7 to 10 days.



On Monday of this week, I walked into a cotton field that is in the scouting program, and saw what I thought to be thrips damage (Figure 1). At first, I was afraid my field scouts and I missed a heavy population of thirps. Once I check about 20 plants within the field it was apparent to me that this was not actually thrips damage, but instead wind damage from the high winds that have plagued most of the area. This damage was caused by our soil getting hot during the afternoon, and then when the picks up the hot blowing sand hits the tender cotton leaves, and desiccates the leaf margins causing the leaves to curl and pucker as they continue to gain size. If you see this damage in the fields, it is best to check to make sure thrips are not the true cause of the cupped or puckered leaves. This can be done by looking at the underside of the leaves to check for thrips feeding damage, and check the terminal and unfurled leaves for actual thrips. Thrips damage appears as sunken silver tissues (Figure 2) that is caused when the thrips use their piercing/rasping mouthparts to rupture the plant’s cell so they can feed on the plant fluids. Kerry Siders, Extension Agent IPM for Hockley, Cochran, and Lamb Counties wrote and excellent description about this type of abiotic damage, and the article can be found on AgFax at http://agfax.com/2017/06/14/texas-west-plains-cotton-not-thrips-its-heat-wind-damage/.



PEANUTS:
                 Peanuts are progressing nicely, and fields in Gaines County have started to bloom this week. If it has not been done yet, now is the time we need to be checking on the amount of root nodules per plant. Ideally, we would like to see 15 or more nodules per plant. To inspect peanut nodulation, one should dig up 3 row feet of peanuts and count the number of nodules on the plant at each site and the number of plants at each site. You can average these for each site and average out these averages, or you can keep a running total for the whole field and calculate the average once finished with the field. If a field averages less than 15 nodules per plant, the field will need some Nitrogen, but still at a slightly reduced rate. If a field averages less than 6 nodules per plant, one should also try to figure out what happened with their inoculant.
Diseases have not been observed in the peanut fields the IPM program is scouting this year, but as we start irrigating our peanuts more we should really keep an eye out for leafspot diseases. Common leaf spot diseases of peanuts for our area include early and late leaf spot (Figure 3). Both leaf spot diseases can look similar on the upper leaf surface, however early leaf spot typically has a yellow halo around the lesion where this is inconspicuous to absent around late leafspot lesions. Spores of early leafspot are typically produced on the upper leaf surface, where late leaf spot usually produces it spores on the lower leaf surface. Use of preventative fungicides around 60-70 days after planting usually provides good management of these diseases, however late in the season another foliar fungicide may be needed if conditions favor disease development.
 

Wireworms and white grubs are still being found in area fields, and in some fields are becoming more common. These insects right now are feeding on secondary roots of the plant which will decrease the amount of water and nutrients taken up by the plant. Later in the season when we start setting pods, they will be feeding on both the pods and roots of the plant. Control options are minimal as there are no insecticides that effectively control these insects. An application of Lorsban has shown to surpress the damage caused by these insects, and depending on the fate of Lorsban with the EPA may be applied if populations are high enough. Foliar feeding worms are still being found, but are very sparse, find no more than 1 worm per a single field. If these insects begin to increased and reach numbers of 8 to 10 per foot in runner type peanuts and 6-8 in Spanish type peanuts insecticide applications may be warranted.


Thank you to all the sponsors of the South-West Plains IPM Program. The sponsors of the program for the 2017 growing season are below.

Platinum Sponsors:

Gold Sponsors:
Doyle Fincher Farm
Golden Peanuts and Tree Nuts

Silver Sponsors: 
Birdsong Peanuts

Bronze Sponsors:
Crop Production Services


New-Tex Gin, Inc.