I threw a leg over the torn saddle, started the motor, and backed the Polaris four-wheeler down the ramp that led from my truck’s tailgate. I let the rig idle while I filled my shoulder bag with material from a five-gallon bucket, and checked the levels in the seeder hopper.

Silica sand coated with mineral oil and dusted in VectoBac Technical Powder made up “the material.” The stuff was benign to all but a few primitive flies, including mosquitoes. If a mosquito larva gulped down a measure of VectoBac, its digestive tract would soon rupture mixing its hemolymph with its digestive juices in what I assume would be a painful end to a short life.

I kicked off my shoes and slid on a pair of knee-high rubber boots then remounted my ride and motored over to a gate in the barbed wire. A throw gate is nothing more than four or five strands of barbed wire strung between two stout sticks. I released one end and threw the works to the side.

Sometimes when I entered a pasture, the yearling cattle would come and investigate. Not today, though. Today, the cattle nearest the gate scattered, I guess assuming the worst–that I was there with a branding iron or a pair of snips. “Jump the fence you dummies,” I said. “We’re going to eat you.”

My search started at the top where the irrigation came into the field and followed the water as it meandered through the tall grass. As it went, the water tended to pool in the low spots of the rolling field, and I focused my attention on these bits of depressed topography.

In the middle of the pasture I got off the wheeler, my boots sloshed in the ankle-deep flow, and a frog jumped for cover.  I grabbed my dipper which is no more than a white, pint-sized cup on the end of a short pole, and squatted to the pool to get a closer look.

Cow paddies floated and turned the clear water the color of weak coffee. Beetles zipped about through the soup, damsel and dragonfly nymphs stalked their prey, and Crane fly larvae crawled along the bottom muck. I scooped at the surface with the dipper and peered into the organic brew. The cup boiled with late instar mosquito larvae. Bingo.

In the heat of the summer, mosquitoes can go from egg to adult in about four days. The trick was to catch them as late as possible before they hatched into biting adults in the off chance that the water would turn off and the source dry up. VectoBac is expensive, and it is far better to save your material and watch the water absorb into the pasture stranding the larvae than it is to treat a source early. This source would not dry in time even if I turned it off myself.

I reached into my bag with a gloved hand and withdrew a measure of material. The Sandman is here, and it is time to go to bed, I thought as I threw the handful into the drink. It sounded like light rain, soft and pleasant. I don’t remember the last time it rained in this desert and found it odd that here, in this place, cool water rose to my shins.

I bent down and looked close again. The larvae went about their business wiggling their way to the bottom to eat around the white seeds of silica.