Fall gardening... coming soon!

This is about the time of year when most Phoenicians say "when is this heat going to break?" And just when we think it is gone for 6 months we get hit with another week of 102+ degree days.  This creates a challenge for gardeners each fall: to plant now or wait another few weeks to make sure the new crop doesn't crisp in the heat.  If you decide to plant early, you may give your new winter crop a jump start on the season, allowing a few more inches of growth and possibly even starting your harvest a week or two earlier. However you do risk losing a number of plants if we have a hot week. No one wants to visit their garden to find their baby greens wilted after a hot day (wilted arugula salad anyone?) So what will it be?  I'm holding out for the week of Oct. 10th for both flowers and veggies, but I will be overseeding my lawn early this year... Oct 1st!  Will I be sorry?  We will have to see.  Wish me and my new green garden friends luck!

Palo Verde Root Borers

I have seen many Palo Verde (PV) trees impacted by the Palo Verde Root Borer: truck and limbs turning golden brown, leaves drop. All these symptoms develop after the damage has been done. But this year I ran across something I have only ever described after the palo verde begins rapidly declining.

I have always told clients to look for broomstick sized holes in the soil under the tree canopy in the middle of summer if their PV begins turning a golden brown. Well how excited was I when I not only discover it at one client's property, but two properties in the same week! (palms sweating from excitement even as I write about it now!)

When I arrived to a property with a recently declined Mexican PV, I was confident what we were looking at was a death due to the PVRB, but a closer look and there was clear confirmation. The nasty beetle had been there, done damage and fled. So if you suspect your PV has declined due to this spiny-legged critter, take a closer look at the ground and look for these broomstick sized holes.

Unfortunately, often times a Palo Verde Root Borer infestation is a death sentence for the tree. Your best bet is to make sure your trees are healthy, watered appropriately and planted at the correct depth. This pest generally will not attack a healthy tree. It does seem to prefer the Mexican Palo Verde and Palo Brea species for a meal.

Troubleshooting Turf Issues

This article was recently featured in the ALCA Influence magazine September/October 2009

How often do you come across that perfect lawn, free of brown spots with the ideal shade of green that makes you wonder why all your properties can’t look that good? That perfectly green turf is hard to come by, especially with all the seasonal changes we have in the southern Arizona climate. If bewildered by that brown patch that just won’t go away no matter what you do, here are a few places to start when troubleshooting a turf problem.
First, you must ask yourself a long list of questions. What changes have recently occurred? Has this problem been present longer than one season? Have the environmental factors been consistent? Look at weather changes and see if there are any parallels in when your turf problem was first seen. Did you adjust and re-adjust your irrigation to accommodate for these weather changes? Many times, turf issues can arise not just from changes in the weather, but also environmental factors we can control, which brings us to the most important question: Did you check the irrigation? Did you re-check the irrigation? Are you confident the irrigation is not the issue? Making sure your turf has the appropriate amount of water seems to be one of our biggest challenges.
If irrigation has been confirmed, we can begin to look at other cultural practices that might be impacting the turf. Is the mowing height appropriate for the variety of Turfgrass? Are my mower blades sharp? Are we regularly changing the mow pattern? Mowing in the same direction overtime can begin to cause soil compaction and create ridges in the turf. If you are able to confirm that some of these cultural practices are not causing your turf issues, you can remove them from your ‘possible causes’ list.
Fertilizers and chemical applications should also be considered. Turf burn is often obvious, but what about that green stripe that stretches down the length of the grass? Is it from a faulty spreader or did the applicator not have it on the correct setting? Did we use a homogenous fertilizer or is it a blended material? Blended fertilizers will often distribute differently when broadcast. Larger particles throw further from the spreader and smaller particles stay closer to the spreader. Using homogenous fertilizers, calibrating your spreader and broadcasting multiple directions can help prevent striping in turf.
Did I use the right herbicide? One chemical issue that is often seen comes from using the incorrect Preemergent herbicide in turf. When managing weed infestations, it is usually recommended for both pre and postemergent herbicides to be used. However, if the goal is to control summer weeds and root-inhibiting preemergents are used, it might be discovered that the Bermudagrass has a hard time tacking down in the treated soil. You might find stolons traveling over top of the soil, but they are unable to connect to the soil and root due to the preemergent barrier used to control weeds. Using shoot-inhibiting preemergents will solve this issue. Again, asking if and when if chemicals have been used will help you discover what is potentially causing this turf issue.
When all abiotic (non-living) factors have been isolated, then we can lean towards the biotic (living) factors that might be causing our turf issue.
As interesting and exciting as “my turf has a fungus” sounds, in our area it just isn’t that common. Sure, we have a handful of pathogens that can plague our turf but they just aren’t seen frequently enough to consider before looking at abiotic causes first. Warm, moist conditions can help mushrooms to surface, often making us think that the turf is being affected by a ‘fungus’. Mushrooms found in patterns can indicate Fairy Ring, but not always. Dig around a bit more and confirm that there is in fact a pathogen present. It is also helpful to get an expert opinion or send a sample to the lab for confirmation before treating with a fungicide that may or may not control that particular pest.
In addition to the few turf pathogens, we also can come across pests that cause turf damage. One of the biggest pests often overlooked is rabbits. They mow down turf in circular patterns, are rarely seen during maintenance hours, and leave behind dropping that are only found when the ground is closely inspected. These patterns can be mistaken for irrigation issues, grubs or pearl scale due to the patterns and it seems the grass will never grow in those areas. Look closely for dropping and see if in fact they are present in the bare areas. Insects like pearl scale, grubs and sod webworms can also cause problem in Arizona turf. Pull back the soil and inspect in the trouble areas to if any of these pests are present.
After exploring potential biotic and abiotic causes of your turf issue and still no success, review your turf fertility program and make sure mineral and salt levels are acceptable for the type of turf you are growing. The key to any plant problem diagnosis is asking lots of questions, discovering the answer and isolating what the issue is not caused by, then moving on to the next potential causal agent. If an issue is occurring on your property, it is likely happening on another property. Call me to see if I can help solve what’s plaguing your Turfgrass.

Protecting Your Trees During Construction

When re-landscaping or fixing irrigation, it is very important to protect the root system of existing trees on your property. Trenching for new irrigation or electrical can damage the root system on established trees, damage that may not be noticed for many seasons after the construction has been completed. Severing large diameter roots can cut off water and nutrients to a large area of the tree, potentially causing branch and limb dieback.

As you can see, a large diameter root was severed to make way for a new lighting system. The root was cut a few years ago, but the tree did not start showing symptoms for at least a year after the project. The upper portions of the tree also contained flatheaded borers, causing additional damage to the mesquite tree. These branches will not likely survive and should be removed to prevent borers infesting other portions of the tree. To make way for the new electrical line, air trenching would have prevented the extensive root damage, borer infestation and branch dieback.

Preparing for Overseeding Winter Turf

As the summer is quickly coming to a close (though not quick enough) we will all be thinking about getting ready to overseed our turf. Just as the Bermudagrass is just starting to look its bests around the middle of August, we begin dropping our mow heights to begin preparing to throw Ryegrass seed around the beginning of October. This can be a very successful process, or it can be a disastrous one that you will pay for the following 3-4 months. Blame it on the weather ‘these 100+ degree days zapped all my seed!’ or blame it on the seed ‘my germination rate was very low this year, it must be bad seed!’ Whatever you decide to blame it on, here are a few keys that will be helpful in overseeding success.

• Check all nozzles before overseeding, just after dropping to your final mow height. Mowing to ½” can sometimes displace your spray head or cause problems. If these problems are fixed after the seed is down, you may run into problems like seed washing away if sprinkler head repairs are required and flooding occurs.


• DO NOT scalp! True scalping of turf is not recommended because of a few reasons:
• Can cause excessive damage to Bermudagrass, delaying its appearance next season
• Scalping stresses out the turf, increasing the risk of disease and insect infestations
• Seed can more easily dry out because there is less moisture- holding thatch and organic matter

• Make sure mower blades are sharpened or replaced just prior to dropping mow height


• When dropping mow heights, ONLY REDUCE HEIGHT BY 30% PER WEEK
• You may have to begin dropping your height at the end of August to safely drop it to ¼- ¾” depending on Bermudagrass variety


• Consider leaving some clippings behind as they will act as a mulch protecting seed from drying out (leaving clippings behind will not cause thatch issues)


• Rechecking irrigation daily at different times of day for 1 week after seed has been thrown
• Irrigation is often the reason for spotty germination or seedling failure, check and recheck often!


• Calibrate your spreader and confirm your square footage
• Too little seed will be sparse and won’t look good until spring, too much seed can choke out each killing seed


• Begin fertilizing within 2-3 weeks of overseeding, continuing to apply fertilizer every 4-6 weeks through the winter and spring
• For recommendations on the ideal fertilizer formulations and fertility programs, please give me a call
  

It is best to wait to overseed until nighttime temperatures are in the mid 50’s or low 60’s. Depending on weather and other environmental factors, you will likely have your first mow about three weeks after seeding or when seedlings are about 3” tall. Good luck out there, and remember cool weather is coming; it may just be November before we see it!

Sucessfully Treating the Agave Snout Weevil

As the Agaves begin wilting out there, I am getting more and more questions about the proper treatment for prevention. The first questions is whether or not to treat. Not treating you take a risk of infestation, which may or may not happen this year or even next year. However, if infested, consider the agave a goner. If you have a large number of plants you want to protect, it can be quite costly to treat.

The key to successfully treating agaves is in the timing of your pesticide applications. Your first application of the season needs to be just prior to insect activity in the spring, which is most often dependant on soil temperatures. As temperatures increase in March, activity of the ASW will begin. If using a 'protective' systemic insecticide, you want to make your application before the weevil's activity. Contact insecticides labelled for drenching can also be helpful in killing existing infestations. Make sure both chemicals control Coleoptera insects, otherwise you will waste time and money with your treatments.

Follow-up with a second application of the systemic insecticide just before the residual runs out. Most professional products provide up to 90 days control if used at the high rates. Contact insecticides often only last 1-2 weeks in the high temperatures so don't count on them for control for more than a short period.

If the Agave Snout Weevil does feed on an agave, you won't know it until the rot begins to destruct the agave, most often in the mid to late summer in the Phoenix area. If they are wilting, don't bother treating these plants. Remove the agave along with the soil around the root ball and try not to plant back immediately. When you do replant, treat the new agave with the systemic insecticide for future protection.

If you would like specific chemical recommendations and the proper timing of your applications, please call me for a customized management program. Remember to keep them healthy- careful not to overwater them throughout the year!

Yeah, these trees are happy. One tree is channeling the Hamburglar!