by Beth Bolles | Aug 2, 2018
Burrow made by the female Cicada killer. Photo Credits: Beth Bolles, Horticulture Agent
During the summer months, landscapes are alive with insect activity. The majority of insects found in home landscapes are not harmful, although the sight of a few may cause some concern. One insect appears to be threatening but is not is the cicada killer, the largest wasp in Florida.
During the warmer months, female cicada killers make ground burrows that consist of several cells for raising a few young. There is an entrance hole, which often remains open, surrounded by a small mound of soil on one side of the entrance. The female makes this ground burrow after mating and then captures cicadas to add to the individual cells. The cicadas will serve as food for the developing wasp larvae that emerge from laid eggs.
Although the females are able to sting, they are not overly aggressive wasps. The males do make more aggressive flights around people but are unable to sting. When enjoying your landscape, just be aware of ground burrows and the flight of the female wasps into the burrows. If you are lucky, you may even see a wasp with a cicada in tow.
Cicada killers should not be treated in most landscapes. If you are unable to tolerate the wasps, you may reduce their habitat by covering open sandy areas with mulch or a groundcover. This does not completely prevent their ability to nest but will certainly reduce suitable nesting spots. For more information on cicada killers visit: http://edis.ifas.ufl.edu/in573.
This article is being revisited as part of our ‘Best Of’ series. August, 2012.
by Sheila Dunning | Aug 2, 2018
Although it has been very hot this summer throughout the Florida Panhandle, many areas have been blessed with afternoon showers several day in a row. Historically, this has been the typical Northwest Florida weather pattern known as the ‘Dog Days’. 
Yet, many landscape sprinkler systems were still running. One has to ask, “Where are all the rain shut-off devices?”. Florida is one of just a few states with a rain sensor statute. Since May 1991, new installations of irrigation systems have been required to include a rain shut-off device. However, no wording was included to cover installation or maintenance. The 2010 statute change now states the following: “Any person who operates an automatic landscape system shall properly install, maintain and operate technology that inhibits or interrupts operation of the system during periods of sufficient moisture.” (Florida Statute 373.62).
Thus, ALL automatic landscape irrigation systems require rain sensors, or other shut-off devices such as soil moisture sensor irrigation controllers. No “grandfather clause” was included for existing systems. Regardless of when it was installed, every sprinkler system must have an operational rain shut-off device. Irrigation contractors can be fined for working on a system without checking out and/or connecting a device.
Moisture sensing technology conserves water, saves money, reduces wear on irrigation system components, reduces disease and helps protect water resources from runoff. Previous research has shown that homeowners using in-ground, automatic irrigation systems, typically in Florida, apply 47% more water for landscape irrigation than homeowners without automatic irrigation systems. This over-irrigation is largely due to a “set it and forget it” mentality despite seasonal fluctuations in plant water needs. If the water costs and the amount of water applied per watering cycle are known, it is easy to calculate how much money is being saved each time the sensor interrupts the program. For example, if a system irrigates ½ acre of turf and is set to deliver ½ inch of water to each zone, approximately 13,576 gallons of water will be used during each watering event. If the cost of the water is $2.00 per thousand gallons, every time the sprinkler system comes on the water bill will be $27.15. A significant amount of money and water can be saved by maintaining a rain shut-off device.
Irrigation is common in Florida landscapes because of sporadic rainfall and the low water holding capacity of sandy soils. Water conservation is a growing issue due to increased demands from a growing population. The least expensive and most common rain sensor device is the expansion disk rain shut-off. Expanding cork disks trigger a pressure switch. The expansion space can be easily adjusted by rotation of the disk cover to a predetermined amount of rain required to trigger the switch. The amount of rain that will interrupt the irrigation system is marked on the adjustment cap. A rain sensor must be mounted where it will be exposed to unobstructed rainfall, typically installed near the roofline on the side of a building.
Irrigation control technology that improves water application efficiency is now available. Soil moisture sensors (SMS) can reduce the number of unnecessary irrigation events. Most soil moisture sensors are designed to estimate soil volumetric water content based on the soil’s ability to transmit electricity, which increases as the water content of the soil increases. Bypass type soil moisture irrigation controllers use water content information from the sensor to either allow or bypass scheduled irrigation cycles on the irrigation timer. Another type of control technique with SMS devices is “on-demand” where the controller initiates irrigation at a low threshold and terminates irrigation at a high threshold. A single sensor can be used to control the irrigation for many zones or multiple sensors can be used to irrigate individual zones. In the case of one sensor for several zones, the zone that is normally the driest, or most in need of irrigation, is selected for placement of the sensor in order to ensure adequate irrigation in all zones. Sensors should be buried in the root zone of the plants to be irrigated. For turfgrass, the sensor should typically be buried at about three inches deep. The placement of SMS should be at least 5 feet from hard surfaces and sprinkler heads. The sensor needs to be calibrated and/or the soil water content threshold needs to be selected.
The amount of water that can be saved using rain shut-off devices is substantial since water use increases substantially during summer months. Remember that every drop that hits the ground will be picking up pollutants as it flows to our groundwater. Nonpoint source pollution is the leading cause of water quality problems. These pollutants have harmful effects on drinking water supplies, recreation, fisheries and wildlife. By only irrigating when the soil needs it, you are also preventing contamination of drinking water.
This article is being reissued as part of our ‘Best Of” series, from August 2013 .
by Larry Williams | Aug 2, 2018
Paper wasp, Photo Credit: UF/IFAS Extension
I respect the fact that wasps can sting when threatened or disturbed. But I also respect the fact that they are beneficial.
Every time I’ve been stung by wasps, I either accidentally disturbed a nest that I didn’t know was there or I intentionally disturbed the nest and paid the price.
Paper wasps are common in Florida. They frequently construct and attach their paper-like nests to building eaves or the ceilings of porches. The adults seek out caterpillars, which they sting and paralyze. They then take the caterpillars back to their nest and place them in individual cells as food for the developing larvae.
I’ve witnessed the paper wasp as it stings and carries away a caterpillar from my vegetable garden. They are busy insects and are doing us gardeners a favor by reducing the population of caterpillars in our landscapes and gardens.
There are other beneficial wasps in Florida. Mud daubers, for example, build their mud-like nests on the sides of buildings close to human activity.
Mud dauber, Photo Credit: UF/IFAS Extension
The mud dauber is not as aggressive as the paper wasp. It rarely stings people. It stings and paralyzes spiders. The mud dauber lays an egg on each paralyzed spider and seals it inside a chamber in its earthen nest. Upon hatching, the wasp larva feeds on the body of the spider. An emergence hole is made as the young wasp leaves the mud nest.
It may not be wise to tolerate all wasp species living in close proximity to your home. Even though yellow jackets, a type of wasp, could be considered beneficial, they are too aggressive and too likely to repeatedly sting to have as close neighbors. I also would be concerned with any type of wasp or bee nest existing in close proximity to individuals with a known allergy to insect stings.
Just because an insect has the ability to sting, it’s not all bad. Wasps can serve a beneficial purpose. But you’ll have to decide for yourself how close to you they can build their nests. The front porch may be too close.
Posted as part of the “Best Of” series, from August, 2014
