A pessimist will say, “Just when you think things cannot get any worse, they will”. Unfortunately, far too many times the cynic is correct and problems compound with resulting destruction and cost.
Sometimes it is the self-fulfilling prophesy of a naysayer, and sometimes it is the voice of experience recognizing a deteriorating situation. In such cases the skeptic, in reality, is the realist.
This concept of foreboding is applicable to a variety of everyday situations most residents of panhandle Florida experience. This includes everything from a fumble at the five yard line to an “October Surprise”, all of which are difficult to overcome.
The second wave of an armyworm invasion can fit in this depressing category, with certain qualifications. The fall armyworm (Spodoptera frugiperda) typically has a hatching flush in the autumn, and they all emerge hungry.
The sight of cattle egrets collecting in a pasture or hayfield is an indication of a fall armyworm hatching. These birds, along with many others, take advantage of the vulnerable and near stationary caterpillars.
Technically speaking, the fall armyworm as well as the southern army worm are not true worms. Each is a distinct species of caterpillar which are the transitional stage of a native moth. Both are in the members of the Lepidoptera (butterflies and moths) order, but each is in a different genus.
Much like their distant cousins the southern armyworm, they are indiscriminate consumers of plant material. A big difference is the fall armyworms will consume a variety of native and forage grasses.
These moths are strong flyers and can travel multiple miles, and the females make every effort to find an ideal feeding location to lay their eggs. Typically the momma-moth will deposit 1,500 eggs during her short life.
Eggs are usually left on the underside of leaves, but if high concentrations of moths descend on a site the eggs may be placed on the top of leaves. In warmer weather the eggs hatch in a few days, but in cooler autumn temperatures it will take a bit longer.
After hatching, the caterpillars go through six distinct phases or instars. With each instar their appearance changes and their ability to eat increases. A distinctive inverted Y shape on their head confirms their identity, if closely examined.
Fall armyworms have been noted for eating a number of commercially important crops, including oranges, cotton, corn and others, though their preference is for grasses and grassy weeds.
This is a chronic concern for herdsmen and hay producers hoping to supply livestock with ample late season forage. It can also be a concern for homeowners and their landscapes, turf and ornamentals, if eggs are deposited in the suburban paradise.
In the last, and most destructive, phase the fall armyworms are about two inches in length with a girth indicating their gluttonous behavior. When they have had their fill, they will retreat to an underground cocoon.
The pupation period may take a week to five weeks, depending primarily on temperature. Warmer weather, typical to north Florida autumns, speeds the process.
In addition to cattle egrets, a number of insects and small mammals consider fall armyworms a tasty snack. The adult moths have to run the gauntlet of night birds and bats during their efforts to find an ideal site for the next generation.
The onset of cold weather reduces activity tremendously. Estimates indicate pupae survivability is reduced by about 90 percent. Still enough survive to rebuild the population the following year.
Curiously, the fall armyworm may eat its younger siblings. If plant material is short, then the bigger caterpillars will eat the small members of their species in an effort to survive.
Even for the fall armyworm population, events beyond their control can make things worse.
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