Early Use of Plant Growth Regulators in Cotton

 

            A cotton plant is an indeterminate perennial, and produces vegetative and reproductive growth simultaneously. PGRs, or Plant Growth Regulators, are synthetic plant hormones that can be used to balance vegetative and reproductive growth in cotton.  When PGRs are applied, there is good potential for change in the plants energy allocation away from potentially wasteful vegetative growth.  Generally PGRs keep developing cells from elongating, leaving the plants with shorter and more efficient internodes.  This does not necessarily increase yield, but it does help keep the plant more compact and potentially more water efficient.  Producers often make use of PGRs at the match head square stage to better prepare for expected hot and dry conditions latter during the growing season. 

            There are three types of growth hormones that PGRs can impact in the plant, gibberellins, cytokinins and auxins.  Gibberellins are most closely related to vegetative growth and promote cell division and expansion.  Most PGRs reduce the concentration of this hormone in the plant, and prevents the cells from elongating, leaving a more compact plant (1).  This compact plant has the potential to be more drought efficient, and consume less water than it would if it were larger.  These synthetic hormones can also alter where the plant tends to bear fruit, and can cause a more compact fruiting zone. 

Plant hormones work in very low quantities, and since PGRs are synthetic plant hormones, they work in very low doses as well.  Increasing the amount of PGRs early will not increase or lengthen their effects.  As the season progresses, PGRs can be applied several times in the season, but they should never be applied to a stressed plant (2).  If they are applied to a plant that is stressed later in the season, PGRs can push a plant to cutout and reduce its yield potential.

We are one of the few areas in the country that commonly uses cotton strippers instead of cotton pickers.  A cotton stripper’s efficiency is at its maximum when the cotton height is below 36 inches.  Another reason to keep our cotton shorter than 36 inches is that tall, rank cotton plants tend to produce too much late fruit or bolls with little hope of maturing before an average freeze date.  This means we need to watch our cotton’s height a little more closely than other regions might need to.  Latter in the growing season, the top five internodes on our blooming cotton fields ideally would average to be about 1 inch in length.  If those internodes start getting larger than 1.2 inches long, it would be time to consider applying a PGR.  Conversely, blooming cotton with internode lengths of 0.8 inches are already experiencing drought stress. 

Applying blanket PGRs very early in the season is not uncommon, especially in this area.  When the cotton reaches the match head square stage, many producers apply PGRs often mixed with a herbicide treatment in the effort to prepare for coming water stress latter in the growing season.  Fields with PGRs applied this early may fare better when the latter stress and heat inevitably set in during boll set.  Right now, our cotton has seen wind damage and has been exposed to some early hot and dry conditions, but few fields can be considered drought stressed yet.  Even in this drought, it should be safe to apply PGR for good benefit as fields reach that minimal match head square stage.

 

Good Luck!                                                                            Please call or come by the office if you have any questions.  Thanks!

                Kate                                                                                                                                     Blayne

 

Written by Kate Harrell, Intern with the Plains Pest Management Association and Texas A&M AgriLife Extension – IPM, Hale & Swisher County.

References

1          http://www.caes.uga.edu/extension/irwin/documents/PGRPublicationUGA.pdf . Philip

Jost,Jared Whitaker, Steve M. Brown, Craig Bednarz. Department of Crop and Soil Sciences College of Agriculture and Environmental Sciences Cooperative Extension Service. Bulletin 1305-Date April, 2006.  6/26/13

 

2          http://agfax.com/2013/06/26/texas-cotton-plant-growth-regulator-considerations/ . AG

 FAX Fields of Facts on June 26, 2013.  6/26/13

Maximizing Pivot Irrigations

 

                As area producers struggle through though drought conditions, most seek to maximize returns from limited irrigation capacity.  Because our aquifer is not refilling nearly as quickly as we are pumping, careful management practices to conserve water are becoming even more pressing.   Many producers are making use of Low Energy Precision Application pivots, (LEPA) and similar pivot systems to maximize their irrigation efficiency.  When on the proper setting, these types of systems use lower pressure regulated nozzles hanging fairly close to the ground to limit evaporation waist and causes by limiting air exposure, crop overspray, and heavily wetting a smaller area of soil surface.   The nozzles of a LEPA type pivot have three settings; bubble, spray, and chemigate.  This allows the LEPA type systems some flexibility and practicality in use. 

                When irrigating a crop for a stand, most producers set their LEPA nozzles to spray mode.  This setting wets the entire soil seed bed and better ensures a profitable stand of young seedlings that cannot search very far through the soil for water on their own, but acts similarly to a conventional sprinkler in water use efficiency.   An older style conventional sprinkler system loses about 20 to 25% of the water pumped to wind and low humidity while it irrigates in normal operating conditions.  LEPA style systems only lose about 2 to 3% while in bubble mode in similar situations.  During very high and sustained winds, something most area producers are all too familiar with, both systems do lose some efficacy but the volume of water lost by conventional pivots is staggering.  In those situations, up to 94% of irrigation water applied can be lost.  The timing for producers to change the settings on their LEPA type systems to bubble mode quickly becomes very important as we face water (and money) loss issues.  To maximize irrigation efficiency, this switch to bubble needs to happen as early in the growing season as possible.

                Cotton, our most pertinent area crop, first becomes capable of searching for its best water source with its tap root system at match-head square stage.  Cotton at younger stages benefits more from the spray mode since it hasn’t developed the root system needed to take advantage of the bubble setting yet.  Producers who make the change to bubble too soon often experience serious stand and or yield reduction without the help of rainfall, which has been severely limited lately.  As cotton plants start getting bigger, they start developing their fruit set and water use increases drastically.  Producers waiting too long to change to bubble mode risk notable yield loss through fruit set, not to mention the painful waist of precious water.

Our area’s cotton fields are ranging from 1st true leaf to pinhead square stage.  For several fields, match head stage is only a few days away.  For this reason we urge producers and consultants to keep close tabs on the stage of their cotton fields.

Have a GREAT day,                                                            Please call or come by if we can help,

Kate                                                                             Blayne

Saving Storm Damaged Trees

Last week on June 5th, Hale and Swisher County experienced a storm that left some rainfall, some hail, and a great deal of wind.  The rain will help green up lawns, but hail and wind left some wreckage behind.  The wind speeds generated by this storm got up to 80 miles per hour, similar to hurricane conditions.  These conditions caused damage to the roofs and trees as well as the crops in the area.  Most of the hail was received in the southern part of Hale County, but high winds caused damage across Hale and Swisher County.

Winds did tear limbs from trees, and is some cases, even knock them completely down.  Trees damaged by severe weather were often stripped of some leaves.  While that is damaging, the problem that holds the largest IPM concern will be the broken and snapped branches.  What is left behind for the trees are jagged and open wounds that are ready targets for insects to attack or infest.  These open wounds heal best if sawed off to a flat surface.  Painting that smooth wound over with insecticidal paint can also help save the tree from possible infestation.  If left uncut and open, the tree could lose fluids and nutrients through continual bleeding of sap, but also wood borers and other insect pests will be attracted to that injury site.  Some of the pest insects that will flock to the tree to feed can spread throughout the tree, devouring it from the inside.  The damage can even lead to the death of the tree.  If insecticidal paint is hard to come by, Malathion mixed with a white or off white paint will work in a pinch.  Saving a tree that has already been infested with some of these pests is costly and often not successful.  Taking these preventative measures now will cost much less and could save an already damaged tree in the long run.

Checking the trees on your property soon after damaging weather events and taking appropriate action by cutting the injury to a flat surface and painting over it with insecticidal paint can save time and money.

 

Good Luck!

Kate

Wind and Hail Damage on Cotton Seedlings

 

Last week, Hale and Swisher County experienced some damaging weather.  The amount of rainfall received ranged from 0.12” to a little over 2”.  Most of the heavier rainfall came down hard and fast, and was accompanied by hail.  Hail can beat the cotton seedlings leaves to shreds or completely off.  The seedlings can survive such a beating from wind and hail if the plant still has a healthy growing point.  The plant can still be considered living if a growing point, terminal or alternate, still remains.  Those growth points should be re-growing leaves and green shoots soon after the damaging event.  Four to five days after a damaging event should be enough time to tell which plants have healthy growing points and which do not.  These plants will be unavoidably delayed, but should have more potential than a late season replant, if there remain enough plants per acre in the field.

We received a great deal of wind along with the rain and hail last week.  Some locations even had wind speeds up to 80 miles per hour.  Wind alone can damage young cotton leaving sand blasted, tattered, and burned looking plants.  Under the right conditions, winds can generate static electricity by lifting small soil particles and bouncing them along the soil surface.  The resulting electric discharge seriously affects seedling cotton as the now electrified particles are carried past. The impact of these tiny static electrical discharges have a cumulative impact upon seedling cotton causing cell rupturing which leads to leaf curl or burn, stem damage, and in the worst cases, seedling death.  Fields do not necessarily have to be ‘blowing’ for this type of damage to occur. 

Sand blasting causes similar damage but wind direction can usually be determined by the resulting damage to the seedling.  Plants along the edges of fields tend to catch more of the damage from wind and sandblasting, especially if they are near a road or any other area with bare ground.  A plant with stalk bruising from wind damage or hail will take longer to recover.  Ground cover or a rough soil surface can help to reduce the amount of damage a field takes.  Wheat trash and other stubble in a field can prevent blowing dirt or any lifting of small particles.  Very few fields in the area have lost large amounts of yield potential to wind damage alone.

Several producers have lost cotton fields to hail while many others will be evaluated this week.  Stand counts will help greatly in determining whether or not a field will make, or if it needs to be replanted.  A minimum of 27,000 fairly evenly distributed plants per acre need to have healthy growth points before the field loses profit potential.  Gaps in a field that are larger than a foot can cause significant yield loss, but cotton can compensate for gaps shorter than a foot if they aren’t repetitive.

Thrips pressure is rising again after a brief respite with the storm, and wind or hail damaged fields tolerate fewer thrips than a healthy field can.  Monti Vandiver, EA-IPM Parmer/Bailey, recommended an economic threshold of 0.5 thrips per leaf stage in hail or wind damaged fields.  Seed treatments for thrips control are showing signs of losing residual, and thrips are reproducing in the fields.

 When evaluating fields this week, be sure to check the stand of plants with healthy growing points, the number of thrips, as well as looking for wind and hail damage.

 

Thank You! 

Kate

 

Kate Harrell is the 2013 intern for the Plains Pest Management Association.  She is a native of Hale County and a veteran of our regional agriculture.  Kate has just finished her bachelor’s degree from Texas A&M University in Entomology and will be starting her master’s degree in the fall.  In between, we are happy to have Kate helping us this summer.  We can expect more helpful tidbits from Kate over the next few months.  Thanks, Kate!

 

Please call or come by if we can be of assistance,

Blayne

Early Season Thrips

          Thrips pressure in the area is higher than I have seen in several years and they are rapidly moving into cotton as it establishes.  At this early stage, predators are a little slow in following the cotton migration. 

Adult thrips are straw colored insects 1/12 to 1/16 inch long.  The wings are fringed and held flat directly over the body when at rest.  Immature thrips look somewhat similar to the adult but have no wings and are somewhat lighter in color.  All thrips have rasping mouthparts which include a single mandible which the thrips uses to scrape and jab host plant tissue.  The thrips then consume the resulting ‘bleeding’ of plant juices.  Thrips often feed in the more sheltered and tender terminal or growing point of the cotton plant requiring very close inspections to acquire an accurate population count.  The ensuing damage causes scaring and malformation of the young leaves at a time when plants need healthy leaves for energy and a good start.  In the worst cases heavy and un-checked thrips damage can become severe enough to damage the terminal and delay squaring for several weeks. 

            Economic threshold (ET) for thrips remains at one thrips per true leaf stage, but there are multiple factors to consider in conjunction with that threshold.  The presence or absence of thrips larva should represent the primary additional consideration.  The presence of thrips larva indicates that the thrips are reproducing in that field and will be there causing damage for some time.  Some other factors include the recognition of light thrips damage, plant stage, and predator populations.  Thrips are one pest producers may want to consider treatments for before thrips reach ET if reproducing populations are confirmed.  Because thrips can move and reproduce so rapidly, thrips can cause serious damage faster than timely applications can be made.

Thrips pressure is progressively higher as we move north across Hale and Swisher Counties.  Our lowest thrips pressure area so far is in southwestern Hale.  Here we are still finding thrips at or above ET.  Cotton planted in dry wheat stubble that have been able to establish a stand, regardless of location, has so far shown the lowest thrips numbers.  Seed treatments and in-furrow insecticide treatments are showing good control for the dollars spent this season.  We have found little or no reproduction in these preventatively treated fields yet but, overwhelming numbers of adults are moving in causing light to moderate damage before being controlled.  I would recommend vigilance in the scouting of these fields for early thrips damage.  If producers will already be treating these fields with herbicides for weed control this week, they may want to consider adding a treatment for thrips to aid the preventative control measures.

Cotton fields with no preventative thrips control applied need to be scouted very quickly.  These fields might be at risk of developing serious and economic thrips damage much earlier than normal this year.  In many of these cases, thrips will need to be controlled as soon as possible. 

Please call or come by if I can help in any way,

Blayne

 

 

 

Controlling Mosquitoes Through IPM

              With spring and early summer rains hopefully coming our way soon and both large field and small flowerbed irrigations firing up, controlling mosquitoes and the threat of disease transmission that they bring is something worth taking a close look at for all of us.  From an integrated approach, mosquitoes are no different from any other targeted pest causing problems.  We need to try and implement as many varying and uniquely different control measures as we can to affectively control our enemy-pests so that they do not become a serious problem. 

For mosquitoes, many of the control measures I will be recommending are preventative in nature and should lower the overall mosquito population in your area and lessen our dependence upon chemical control alone.  We must have a plan in place to control mosquitoes before they try to ‘carry us off’ from our backyard activities or we hear reports about the alarming numbers of West Nile cases in our area hospitals.  Preventative control measures do require a proactive effort.  None of these mosquito IPM strategies I will be sharing are very time consuming, nor do they cost a tremendous amount to implement and I feel that you might be pleasantly surprised by the results.

                Understanding our enemy is the first step toward sound IPM.  There are multiple and numerous species of mosquitoes that haunt our area.  All of these species of mosquitoes require water to complete their life cycle.  The aquatic larval life stage of mosquitoes are referred to as wigglers.  These wigglers are harmless.  In most aquatic ecosystems, wigglers form the base of the food chain.  Even most adult mosquitoes pose no threat to humans.  It is only the female mosquito that parasitically feeds on blood, and she only does that when she is ready to lay her eggs.  These females utilize blood for a protein boost to both give them the energy for the monumental process of laying possibly hundreds of viable eggs.  When these female mosquitoes are ready for a blood-meal, they become almost super parasites with some truly amazing abilities to seek out and successfully feast upon unsuspecting victims. 

These facts usually set people to thinking about just how many mosquitoes there really are around us all spring and summer.  It can be staggering to think just how bad mosquitoes would be if they were full time parasites.  That fact set aside, hopefully we can make note of some weaknesses in the mosquitoes’ life cycle that we can attack. 

Mosquitoes must have water to complete their life cycle.  My first recommendation for lowering the mosquito population in your area is to deny them that water.  That is easier said than done.  Even in the midst of the current drought, we have not been mosquito free.   That is because mosquitoes do not require very much water.  In fact, some of our most dangerous disease vectoring mosquito species can complete their wiggler larval stage and be ready for adulthood in as little as a cup of water and in about five days, temperature depending.  That ability makes completely denying mosquitoes access to water impossible.  However, with vigilance we can significantly lower the mosquito population through limiting the availability of that standing water. 

                We can limit that water by doing a few little things.  Mosquitoes can easily reproduce in things we often overlook.  A child’s toy left unattended in the back yard that catches rain or yard sprinkler water, a pet’s outdoor drinking bowl, livestock tanks, uncovered rain collection barrels, or that water holding pothole in the back alley are all viable examples of places that mosquitoes will choose to lay eggs and successfully reproduce.  In every one of these examples, we can limit mosquito reproduction.  The child’s toy can be picked up or water emptied, the pet’s drinking water can be changed every four days, livestock tanks can be stocked with predatory fish, rainwater collection barrels can be made air tight, and potholes can be filled or drained. 

                Another opportunity to lessen the mosquito population occurs when they are young adults.  Young adult mosquitoes do breathe air, but remain partial to cool, damp, and shady areas.  Locations like tall grass, weedy patches, or horticulture features that include tall plants are all prime haunts for mosquito hideouts.  By keeping the grass and weeds mowed or controlled near your house or barns should seriously limit mosquito’s access to your family and livestock.  A nifty horticulture feature in your yard that involves tall, shade offering plants can be treated with insecticides to kill mosquitoes before they move to attack.  Often cities, communities, and owners of county homes proactively treat large areas for mosquitoes.  The product Malathion is commonly used for this purpose.  While Malathion is proven to be predictably safe to humans and the environment it should be handled with respect and with adherence to safely.  If this is an option for you to treat an area for yourself, please follow the label.

                Finally we come to dealing with the female mosquitoes that are actively seeking a blood-meal.  You might have heard of some of these before but they still make good sense.  When venturing out doors, always wear a proven form of mosquito repellent.  Products containing the active ingredient DEET are all proven to repel mosquitoes.  Picaridin is a newer, differing active ingredient and shows some real potential as a mosquito repellent.  

There are several ways to limit our exposure to mosquitoes.  Mosquitoes prefer to remain inactive during hotter hours of the day.  For this reason we could avoid going outside during dawn, dusk, or night time hours during mosquito season if possible.  Wearing long sleeve shirts and pants when venturing into mosquito habitats can also prevent some mosquito bites.  Making use of light traps or bug zappers, sticky traps, etc. will also nab several mosquitoes before they are able to find a blood-meal.  

Hopefully we have shared some ideas with you that will keep those mosquitoes at bay this summer for our community and families.  Please call or come by my office if I can help in any way.  Good luck,

Blayne

Soil Temperatures - May 15, 2013

This should be our last soil temperature reading shared here and it is the one everyone has been waiting on.  Planters have already been rolling for the majority of this week getting cotton in the ground and rightly so.  Soil temps have been just warm enough that when the upcoming weather forecasts were considered, the conditions are considered finally advantageous for cotton seedlings.  Just in case a grower has been waiting on planting cotton until temperatures were just right, I took one reading yesterday, May 14 at 2 pm, and one this morning at 7:45 am. 

 

-          69°F.  Halfway, Texas (5-14).  Potential cotton / moderate moisture / plowed / pivot irrigated.

-          64°F.  Three miles north of Kress (5-15).  Potential cotton / good moisture behind irrigation / plowed / pivot irrigated. 

 

The 64°F degree reading was taken less than 24 hours behind a pivot application of water.  This may represent how the temperature of the water cools the soil.  In situations like this, with hot days forecasted, the soil will warm well before the ground will support a tractor.  Just a few degrees cooler and there might be some concerns.  Now most of our concerns about soil conditions and planting can return to seed bed moisture content, early season pest and weed considerations. 

Please call if I can be of assistance.

Blayne