Monthly Archives: August 2014

Smart Irrigation Month Tips

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Stripling Irrigation Research Park has the Smart Irrigation Month campaign to send out tips to our clientele throughout the month of July. Here are 2014’s tips:

Tip #1 – The average life of a sprinkler head / nozzle is about 7 to 10 years. Check your center pivot application uniformity by having a “catch can” test performed, fix leaks, and replace worn nozzles. Nelson (www.nelsonirrigation.com) and Senninger (www.senninger.com) make several types and models of sprinklers.

Georgia Soil & Water Conservation Commission (gaswcc.georgia.gov), USDA-NRCS, or your local UGA Extension Service office can provide assistance.

Here’s a link to a UGA extension publication on uniformity: http://extension.uga.edu/publications/detail.cfm?number=C911

Tip #2 – UGA’s Calvin Perry (Stripling Park) and Wes Porter (Extension Irrigation Specialist) have put together a Center Pivot Spring Check List. It includes items to get your irrigation system in top shape. Many of the things covered can be applied to your system year-round.

Tip #3 – A quick way to increase the efficiency of an ag irrigation system is to repair all leaks on the center pivot or other type system as soon as you notice them. Buried pipes seldom leak. However, above ground pipes frequently have worn gaskets and considerable amounts of water (up to 30%) can be lost before it gets to the actual discharge point (sprinkler). Replace leaking gaskets, boots, etc. and plug any holes in the pipes.

Tip #4 – Variable Rate Irrigation (VRI) is a tool of precision agriculture that optimizes irrigation water application. UGA and SIRP have been at the forefront of development and adoption of this important technology. Research shows that implementing a VRI system can result in water savings averaging 15% vs. conventional water application.

For more info, go to http://striplingpark.org/agricultural-water-conservation/ and scroll down to Variable Rate Irrigation.

Fullscreen capture 8132014 55025 PMTip #5 – To practice smart irrigation, consider using soil moisture sensors to help you decide when to trigger irrigation on your crop/field. There are a number of commercially available sensor systems, such as AquaSpy, AquaCheck, Decagon, John Deere, Irrometer, Sentek, etc.

Over the last years, University of Georgia researchers, led by George Vellidis, have been developing their own affordable system – the UGA Smart Sensor Array – consisting of Watermark soil moisture sensors, temperature sensors, wireless mesh radio transmitter, and base station with cell modem. A web portal provides secure access to the soil moisture data.

For more info, go to http://vellidis.org/research-projects/smart-irrigation/uga-smart-sensor-array/.

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Black Pecan Aphids And Scorch Mites

BlackAphids-003We’re seeing evidence of black aphids and mite damage on pecan leaves. Growers are spraying for both right now. August is a critical month for pecan production since the female flowers are induced. UGA Extension Horticulturalist Dr. Lenny Wells says while flower induction is driven primarily by the effect of crop load on the tree, additional stresses like drought, insects, disease, sunlight, etc. in August can significantly reduce the following year’s crop. The trees need to undergo as little stress as possible.

Many growers have already been spraying for black aphids. Schley, Sumner, Gloria Grande, and Oconee are more susceptible to black aphids and treat before levels build. Large populations usually build in August, Septemer or October. Feeding causes bright, yellow spots between the veins of the leaflets. The spots soon die and turn brown. A few dead areas can cause a leaf to shed, and we are seeing leaves shed with black aphid damage (left).

PecanScorchSpiderMite-1We’re also seeing damage from mites. Dr. Lenny Wells says, “Mites (right) are a little tougher to know when to pull the trigger on. They can be found in the orchard throughout much of the year and normally don’t reach population levels that do harm. The trees can tolerate them to a point. But, like certain diseases that lay in wait until the right conditions are found. When it gets hot and dry in late July/August and you see a strong mite population on the leaves, they can explode rapidly as black aphids, causing severe scorching and defoliation. This normally occurs following a spray with a broad spectrum insecticide but it’s not always the case. I have seen this in orchards where no broad spectrum insecticides were used. Therefore, growers should be vigilant of mites and watch for signs of early scorching which begins along the midrib of the leaflets. Miticides are expensive so we want to be sure that there are mites present before spraying. There are many things out there that can scorch leaves and a grower can waste a lot of money spraying scorched leaves rather than mites.”

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Filed under Entomology, Pecans

Soybean Update

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I was out for a while this morning checking soybeans. We have many different growth stages throughout the county. Except for soybeans planted behind corn, most of our younger soybeans are now at bloom stage. Later planted soybeans are beginning seed development, about R5. So far, Asian soybean rust has not been detected in GA.  One thing we are seeing is downy mildew (below). In some fields, yellow spots appear on the leaves. Sometimes under them, you will see some gray-brown ‘down’ where sporulation is occurring. This is not an economical issue of soybeans and we do not need to spray for this.

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I noticed some leaves with caterpillar damage. From full bloom up to pod-fill, we treat when the leaf defoliation level reaches 15%. From the 2014 UGA Pest Control Handbook, it usually requires an average of 8 or more green cloverworms, loopers, or velvetbean caterpillars per foot row to cause this much defoliation.

Also, we’ve been seeing some adult whiteflies. We need to continue to monitor their progress. UGA Extension Entomologist Dr. Phillip Roberts says reports of whiteflies in Tift, Irwin, and a few surrounding counties so far.

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El Nino Chances Decrease

Here is an update from UGA Extension Climatologist Pam Knox:

The pool of unusually warm water in the eastern Pacific Ocean that was observed earlier this summer has now mostly dissipated without a response from the tropical atmosphere, leaving climatologists wondering if El Nino will occur this winter as predicted earlier.  In the strongest El Ninos, the atmospheric signature of El Nino is starting to be visible by August, and even weaker El Ninos often show some El Nino circulation patterns by late summer.  It is not too late for an El Nino to occur, but as time goes on the likelihood of a strong one decreases.  Climatologists still think that we may see a weak El Nino develop this fall, but the impacts of a minor El Nino are likely to be restricted to south Alabama and Georgia and south into northern Florida.  Weak El Ninos generally provide wetter and cooler conditions than normal in these areas, but there is a lot of room for other patterns to dominate the climate when El Nino is weak.

The prevailing large-scale weather pattern this summer has been a persistent high pressure area on the west coast of the US and a matching broad low pressure trough across the eastern US.  The high pressure in the west is linked to unusually warm water in the Gulf of Alaska which has been in place for several months.  The high pressure in the western US has led to frequent periods of above normal temperatures and an increase in drought conditions over time, especially in California.  Farmers in California were looking to a strong El Nino to bring drought relief to the area and are now concerned the drought may last for a fourth year or even longer if El Nino does not materialize.  Meanwhile, in the east, the cool flow of air from Canada has kept temperatures cooler than normal for a good part of the summer, although only a few daily records have been set.  Rainfall was plentiful earlier in the year but abnormally dry conditions have started to spread through southern Georgia and into Alabama.  A small area of moderate drought has developed near Alma, where they set their record lowest July precipitation since 1948, a total of just 0.41 inches for the month compared to a normal of 5.33 inches.

There are no immediate signs of the warm Alaska waters going away, which may keep this persistent pattern in play for fall and perhaps even winter.  That would mean that winter this year could be cooler than normal; a higher chance of snow and ice storms could be possible if this pans out. Climatologists will continue to monitor the situation to see whether or not an El Nino starts to appear later this fall

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Pond Weeds – Filamentous Algae

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I was asked to look at a pond on the Thomas/Brooks line with weed problems. There was quite a bit of torpedograss along the edge. However, we are starting to see algae show up in ponds. Copper complexes are good control options for all algae. Diquat also works well with filamentous algae. This pond has already been treated. UGA Aquatic Specialist Dr. Gary Burtle says one thing to remember is that these herbicides last for about a week, then algae may regrow. For this reason it is recommended to also stock grass carp at 10 per acre to maintain control.

It is still very hot and with fish in ponds, it is best to either treat after we start to cool in the fall or treat very small sections of the pond at each time. Treatment will control the torpedograss for a month or more. Retreatment my not be necessary this late in the summer, but torpedograss treated with glyphosate in early summer will require another application. Use a 2% solution of glyphosate and an adjuvant (surfactant or sticker/spreader).

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August Peanut Water Requirements

EddieRedding-Cotton-Peanuts 007Since July 25th, the Georgia Weather Station shows no rainfall measured in Dixie, GA. Our 6 month average rain is not bad, but recent dry weather is causing more issues with crops. We have been needing rain for a few weeks now and soil is really dry. UGA Extension Agronomist Dr. Scott Tubbs says whether peanuts were planted in April or June, weather conditions are dry for a critical reproductive development time. Peanuts are setting blooms and filling pods with too less moisture. The majority of the harvestable peanut pods initiate from around 35-40 days after planting through around 90-95 days after planting.

UGA Extension Scientist Dr. Gary Hawkins has this to say about water requirements for August:

The first week of August (if the peanuts were planted by May 1), is the peak of the water use curve, requiring about 2.1 inches per week.  The good news is that we’re about to move past the peak water use period and start requiring less water.  If your peanuts were delayed by 2-4 weeks they will move into the highest water used period soon.  Please see the figure below for the ranges of peanuts planted from late April (yellow) and peanuts planted in middle May (blue).  Hopefully we’ll begin to pick up some more rainfall to help with these water requirements.

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