Question

I have a number of bermuda grass lawns that get bare spots in them when the grass comes out of dormancy. It takes about half the summer for the grass to grow over these spots. They are telling me it is fungi that is hard to control. If I use Pendulum Aqua Cap on these lawns will it slow the process of the grass growing into these dead spots? Second question: Many people around here scalp their bermuda grass lawns and use power rakes on them. Are they taking the pre-emergent off when they do that?

- Monty, Malcolm., TX

Answer

Everyone has questions. And BASF Professional Turf has answers.

You ask two excellent questions and I will try to do them justice.

The easier one is the second:

In general to keep your weed barrier in tack for as long as possible it is highly recommended that you do not do any additional mechanical work on these lawns or you run the risk of disturbing or breaking that weed barrier and causing weed control to not last as long. You break the barrier and it provides the opportunity for weed seeds to germinate as they blow in to the surface or you bring them up from below the treated zone.

First question on the possible disease and what to do:

You have one of two problems on this turfgrass and I recommend that you have it properly identified at the Plant Diagnostic Clinic at Texas A & M. Dr. Kevin Han or Dr. Young Ki both are familiar with this problem. Send a sample to the lab at the time of spring green-up - take the leading edge of where you see the disease developing in the turfgrass. The problem is most likely caused by bermudagrass decline organism known as Take-All - Gaeumannomyces graminis var. graminis. Or- it is caused by the organism I just mentioned combined with possible others and the problem is described with the name Spring Dead Spot. Because you mention that the turfgrass grows back I tend to think you only have the one organism causing Take-All and that would be easier overall to get under control.

We actually did the trials at T & M on bermudagrass and found that if you have this reoccurring problem you should make fungicide application in fall and then repeat in the spring. Best timing with our products Trinity or Insignia fungicides were Oct. and Nov. and then repeat in Feb. and March (just prior to green-up). Both products work on this problem. You do need to eventually do those fall applications but for this year you could see if a spring only cycle of two applications 30-days a part provide essential protection.

If you have this problem then I would use a product like Drive XLR8 on the crabgrass as a early post application and not do a DNA herbicide application until the second round in late May or early June. DNA herbicides could initially slow the turf from growing back in when first coming out of dormancy.

Hope this is helpful-

Regards,
Kathie