Monday, August 12, 2013

Feeling Bugged About the Latest Bug Discovery

We see a lot of bugs every week. There’s navel orangeworm in almonds, beet armyworms in alfalfa and lygus in cotton to name a few. Sometimes, we discover something unusual.

Last week was a perfect example.

Carlos found a bug that may be a spotted alfalfa aphid.
While scouting some alfalfa fields last week, field scout Carlos Silva caught some aphids that appeared to have spined black spots on their backs. In another alfalfa field a half mile away, he found more of the same. It was quite unusual since Carlos hasn’t run across these kinds of aphids in other fields across the valley this season.

His suspicion is these may be spotted alfalfa aphids. Introduced in New Mexico in the early 1950s, these aphids will suck the juice out of leaves and inject a toxin into the plants. Plant growth can be stunted and a sticky honeydew can developed on the alfalfa. Carlos is asking Dr. Pete Goodell of UC IPM to check them out.

On the cotton front, Carlos reports most plants are at three to five nodes above the white flower, which is used to determine when cutout takes place. Cutout means the cotton bolls are mature and roughly 95 percent of the crop has been set. This provides a good indicator of the future yield. As a rule, cutout occurs at five nodes above the white flower.

The good news at cutout is growers can cross out one pest from the watch list – lygus. Spider mites and aphids will be the main threat.

Meanwhile, almond field scout Jenna Horine says some growers have been treating for mites before harvest despite following best management practices. Many problems surfaced from neighboring farms that kicked up dust from the dirt roads, driving the pests into the orchards.

As a result, growers spend money treating for mites even though their operation wasn’t responsible for the flare-up. To solve this problem, some growers are talking about digging potholes into dirt roads to slow down speeding drivers. Our message: Be a good neighbor and slow down.

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