Mid-Coast IPM

This week I was able to visit a field of grain sorghum in DeWitt County that was infested with pasture mealybugs.  The field was ready for a harvest aid application and the grower's concern was the mealybugs may go to the heads after the application and get everything sticky with honeydew.  Pasture Mealybugs on Grain Sorghum Photo by S. Biles Most of the plants had many mealybugs per leaf, generally toward the base of the leaf on the underside. The grower indicated the mealybugs were all over the 60 acre field. We walked a few hundred feet into the field and found them everywhere we stopped. They didn't get there recently; but were first noticed in early June. The mealybugs were found on the lower leaves but caused significant damage to those leaves and the upper leaves were not as green as they should be. I suspect the mealybugs likely caused some yield loss.  While there was sooty mold on the lower leaves, very little honeydew was noticed, and it was not very sticky whe...

Will the pasture mealybug be moved in hay bales?  This is one of the many questions asked over the past year. My thought has been, yes, the mealybug can move in hay bales, but we have no research on this topic. The problem with the mealybugs staying in cut grass is, as the grass dries, there is less plant sap for the mealybug to feed on. So the logical assumption is the insects will leave the grass.  A few weeks ago, Dr. David Kerns shared some data on this showing most mealybugs left the grass but about 5% were found in the cut grass 48 hours after cutting. I conducted a similar research test on a field of WW-B Dahl grass near Port Lavaca. The results were similar to those of Dr. Kerns. In the Port Lavaca Test, about 100 mealybugs were found in a similar amount of grass as the 2 sq ft samples taken prior to cutting the grass. This is 8.7% of our pre-cutting counts. The test is planned to be continued by sampling the hay bales for live mealybugs. More to come...

1.       Scouting a.       Check edges of damaged areas more than in the middle of dead grass. b.       Look for leaf damage symptoms such as yellowing and red leaves. c.       Look for mealybugs on the underside of leaves, especially the lower leaves. d.        Check the soil surface and thatch below grass canopy for mealybugs. Often a majority of the mealybugs may be in the thatch and on and in the soil. e.       Mealybugs can be as large as 5 mm in length or as small as 0.2 mm. If larger mealybugs are being found, there may be many more small mealybugs that are difficult to see. f.         We have not determined a producer/consultant method for determining the size of the populations while in the field. However, if mealybugs are easily found, they are likely above an economic level. 2.    ...

We are at the time of the growing season where our primary insect pest is stink bugs. This is the case in sorghum, cotton and soybeans. While each crop has its own species causing damage, the fields are important to scout to identify the pests causing potential yield and quality losses. In grain sorghum, many fields are being harvested but there are some fields that are still susceptible to stink bug injury. The primary stink bug of concern in sorghum is the rice stink bug .  The economic threshold for stink bugs in sorghum changes as the crop matures; becoming less susceptible as it approaches hard dough as depicted on the graph below.  For detailed information on the economic thresholds of stink bugs in grain sorghum, look HERE . We are also finding sorghum aphids (AKA sugarcane aphids) in a number of fields in Refugio County. Check these fields to prevent harvest issues from the honeydew produced by the aphids. Cotton is also susceptible to stink bug damage from early bloom...