Texas – LRGV: Sugarcane Aphid In Sorghum; Boll Weevils, Thrips, Aphids in Cotton

A colony of sugarcane aphid on the underside of a sorghum leaf. Photo: Dr. Mo Way, Texas AgriLife

Hi everyone!

It’s been pretty busy already this growing season as many crops, grain sorghum, cotton, and corn were planted a month early due to the unseasonably warm weather we are having down here in the Lower Rio Grande Valley. Our days have been in the low 90s and our nights in the lower 70s. We started off the year with some good moisture and now with these high strong southern winds it has been getting pretty dry. A lot of you all will start irrigating within these next two weeks. Lots of pest activity in all crops so the need to monitor your crops this season is very important!

COTTON

Lots of cotton planted this year and still being planted. We have cotton in all stages right now. Some of the earliest cotton is already pin head squaring and then we have some cotton just coming up at cotyledon stage and everything in between. According to the Texas Boll Weevil Eradication program we have of as to date 165,000 acres of cotton planted and coming up. As of March 1st of this year we had already about 30,000 acres of cotton planted which was incredible!

As of January 1st of this year to date the Texas Boll Weevil Eradication Program has trapped 470 boll weevils and continues to work hard each day to protect our cotton crop. Mexico this year has planted 9100 hectares, that’s 22,477 acres planted this year, double of what Mexico planted last year.

The Texas Boll Weevil Eradication Program wants you to keep these 3 things in mind to protect your cotton crop:

  1. Report all cotton acreage to local boll weevil or FSA office by the FSA certification deadline,
  2. protect your boll weevil traps in the field, and
  3. clean your harvest equipment

We are seeing high numbers of thrips mainly down by the river and in cotton fields planted near onion fields being harvested. Also finding thrips in the mid valley, not as bad but still they are there. Many fields are being infested with cotton aphids but I am seeing beneficials moving in and doing their job to control them, but still some of you all have already had to spray for cotton aphid, especially down by the river. Seeing a bit of spidermite activity in cotton and picking up on whiteflies already this growing season.

I have not seen any fleahoppers as to date but feel we will definitely start to pick up on them within the next two weeks as pin head squaring has already begun in a lot of the earlier planted cotton this year. Be mindful of all pests in your cotton fields as your spray applications you spray out will not just be for one pest this season but for a combination of pests. I already picked up on a couple of bollworms in some 5 true leaf cotton down by the river this year so be mindful of that as well and if you have any questions or concerns, call me.

GRAIN SORGHUM – SUGARCANE APHID

We are monitoring grain sorghum in all three counties. We have already picked up on sugarcane aphid in commercial grain sorghum in all three counties: Hidalgo, Cameron and Willacy. Last week my technician and I found the first sugarcane aphid alates and nymphs in a sorghum field near the river in the Donna area. Then this week the same field started to show a couple of leaves with populations of 400 aphids per leaf, this field was sprayed Wednesday.

These sugarcane aphids are migrating and populating fast.

Wednesday I was in the mid Valley in the Edinburg- Elsa area and picked up on some sugarcane aphid alates and nymphs in the sorghum there. As well as yesterday, Thursday, on the west side of Edinburg near Depot Rd and Monte Cristo Rd I was finding sugarcane aphid alates and nymphs (about 10- 15) as well. Then today in the morning I was in Faysville and found a couple of leaves in a sorghum field with 1 alate and 3-5 nymphs, so barely starting to populate there and the grain sorghum was in the V8 stage.

I did not expect them to migrate to the mid Valley until next week but  but with these strong southern winds from Mexico they are migrating fast. In fact, yesterday I sent my field technician Alma to Lyford and she found the sugarcane aphid barely starting to migrate in (alates) and lay some nymphs, but again barely starting in Willacy. She was also in the Rio Hondo area on Tuesday and found them in a sorghum field just booting as well, we also have sorghum booting and starting to flower in west Edinburg close to Mon Mack and Monte Cristo Rd.

So they are wide spread and starting to populate fast with this heat and strong southern winds, so it is very important to be monitoring your sorghum these next two weeks for sugarcane aphid populations. A lot of you guys will be irrigating your sorghum in the next two weeks since it is so dry, please check your fields for sugarcane aphids and spray if you see them before you start irrigating because the populations will get away from you all if you don’t due to the moisture and the heat.

You guys know what to do, and I’m very proud of my Valley growers but the timing this year is 2 to 3 weeks earlier than what you guys are used to spraying at. This is due to the fact that everyone planted pretty much a whole month earlier this year compared to the last 4 years we have been monitoring the sugarcane aphids. Also this year it has been unseasonably warm early on, so the heat units are there for the plant stages, V8, to be there for the sugarcane aphids to move in.

The sugarcane aphid is here in the LRGV and from what I can see from my observations is it moves into fields and populates them when your sorghum is at V7, mainly V8 stage prior to booting. I believe that seed treatments do not prevent the sugarcane aphid from moving in to your sorghum field early, nor is it the time of the year that brings them in, because if that were the case it wouldn’t matter what stage the sorghum was in we would not start seeing them move into commercial sorghum until mid-April like we have the past 4 years monitoring them and collecting phenology data. Nope, I believe it is the stage that they prefer because every sorghum field I have seen them in that has them is at V7, or V8. I have checked many sorghum fields around the Valley at V3, V5, V6 and have not seen them move in until the V7, and V8 stage prior to boot.

I have a sorghum variety trial that Beto helped me plant on Hiler farm here in Mercedes and I was mad because I planted so late, March 6th , but now I am happy because it allowed me to confirm this. In my sorghum variety trial all the seed have NO insecticide; they only have fungicide and safener for herbicide protection, but no insecticide. My sorghum variety trial is at V5, V6 stage right now surrounded by other sorghum from the South, East and West at V8 stage and guess what, the sugarcane aphid is barely starting to populate the V8 sorghum surrounding my trial with a few alates and barely starting to lay nymphs from what my technician Alma and I saw yesterday, Thursday.

We saw a little corn leaf aphid in my variety trial which was to be expected since no seed treatment but we did not see any sugarcane aphids. I expect to have them move in next week when my sorghum is at V8 stage. The reason why I would like you all to control populations now when they are very low is 1) the residuals will last longer and 2) I predict that if this heat continues that the second peak for sugarcane aphids will come early and will be the last week of May instead of the third week of June and you all may have to spray prior or during harvest. So I would like you all to avoid having to make two spray applications now because populations got away from you so we can save the second spray for prior to harvest, now here’s hoping that will not happen but just trying to convey what I see might happen. However if the weather changes and we get those overcast days then it’s a different story.

Now don’t get me wrong seed treatments are great, and I believe they are keeping you guys from having any problems with the Yellow sugarcane aphids this year that moves in on those lower leaves, because I have, along with other consultants noticed damage that looks like Yellow sugarcane aphid damage but have not seen any Yellow sugarcane aphids in fields as of to date, so that’s good because last year we had lots of problems with them.

The 2 products available to spray for the sugarcane aphids this year are Sivanto and Transform. Sivanto spray at 4-5oz/acre, do not go lower than 4 oz for good residual and Transform is already available since we received the Section 18 sometime in late January and you will want to use that product at 1-1.5oz/ acre, do not go any lower than 1 oz for good residual. I also want to share with you all that Mexico has grain sorghum in the soft dough stage and has been having high populations of sugarcane aphids and has been spraying many fields in the San Fernando, Tampico, and Rio Bravo areas according to my friend and entomologist Dr. Jesus Vargas. He has shared with me these pictures of sugarcane aphids on sorghum leaves in very high numbers Also he shared with me a picture of a sorghum head that has aphids feeding on it but they are blue, green in color and are not the sugarcane aphid. We are trying to figure out what species they are. Now if you guys encounter any blue, green aphids feeding on your soft dough grain sorghum in the weeks ahead please call me so I can go collect and investigate this, but here’s hoping these winds will calm down and we won’t get them, just saying, keep my fingers crossed.

Corn

So happy to report that there is nothing going on in corn, well as far as pests go from what I have seen scouting a few fields here and there! There is this year a lot of corn planted everywhere though, and a lot of corn in Willacy County. We have corn in all stages (Fig 9). We have a lot of corn in V3, V7 and V10. There has been a little fall army worm activity but that’s nothing new. Also there was some fall army worm activity in grain sorghum but mainly in Willacy County and the Rio hondo area.

 

 


The Latest


Send press releases to Ernst@Agfax.com.

View All Events


Send press releases to Ernst@Agfax.com.

View All Events