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‹ The Weekly Green

1930 Invasions

June 22, 2016

It has been a bit hot of late and the omnipresent buffelgrass is dry like tinder and ready to burn. Buffelgrass likes fire, because it kills off its competitors, such as the saguaro,  while its seeds survive the heat with ease.

For the past 8 years, the Southern Arizona Buffelgrass Coordination Center has spearheaded efforts to control this menace. Now, come June 30 its activities  will be taken over by the Arizona-Sonora Desert Museum, the Pima Association of Governments and Sky Island Alliance, combining their resources for this difficult fight. SABCC’s website will be maintained by the Museum and continue to be a great help in identifying and controlling buffelgrass.

The most efficient way to kill buffelgrass is with the herbicide glyphosate, commercially available as Roundup , Kleenup or  Rodeo, which is  the one to use when you are spraying around water. It should be applied when at least half the leaves of the plant are green; then it will also kill the seeds, which otherwise remain viable. Glyphosate kills everything so spot-treating the plants will minimize harm to the surroundings.

Buffelgrass was introduced in the 1930s to supplement the meager grazings the Europeans found here for the cattle they brought.

Crayfish a.k.a. crawdad

Many other invasive species were introduced around the same time, among them the crayfish, being the live bait of choice in Europe.

Crayfish have become a serious pest in arizona, because they devour everything aquatic, including the vegetation that reoxidize the water and provides the fish with cover.

  Good eatin’!

However, because they eat everything, they are good eating themselves too; crayfish fishing is a fun outdoor family activity. No limit! Only, you have to eat them where you catch them, because Arizona law strictly prohibits transporting them anywhere else.

With the summer heat come the ants. It is thought that there are a million ants for every human and that their total biomass is comparable to ours. The level of organization of some ant societies is comparable to ours too. They aereate the soil and remove dead matter; making them an important indicator species for biodiversity. Ants were the first form of biological pest control, used by the Chinese since at least 400 A.D. to protect citrus orchyards. Moreover, they can also be used to suture wounds by having them pinch the wound with their mandibles and then cutting off the body – a trick that may come in handy when you’re out hiking way out in the wilderness.

Fire ant

Make sure not to use fire ants for that, though. As their name indicates, the venom of these invaders from South America causes excruciating pain and nasty blisters. They get very aggressive when they perceive a threat to their nest and they are quick to do so.

fire-ant-infestation-mapCoincidentally, they also arrived in the US around 1930. The FDA estimates that by now fire ants cost the US economy more than 5.5 billion dollars annually. One approach to combat this huge infestation is the introduction of the phorid fly, its natural predator, in the southern US.

While we wait how that will pan out, what to do when stung? First of all, do not scratch at the blisters, however hard that is. Scratching will irritate the affected area even more and greatly increases the risk of infection. If the blisters are left alone, they flatten out and vanish after a few days. Some relief may be found in treatment with aloe vera, vinegar or urine.

(Broadcast 3:40)



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