Monday, May 12, 2014

There’s No Time to Get Sappy Over Almond Pests

Sometimes Mother Nature likes to play tricks. Just ask almond growers.

Take a look at these photos. You’ll notice oozing sap coming out of the green hulls. What’s the cause? If you said leaffooted bugs or stink bugs, then give yourself a hand. Maybe.
Jenna Horine shows sap caused by leaffooted bugs.

Field scout Jenna Horine reminds growers that they can’t judge a hull by its outward appearance.
Indeed, wild swings in temperatures – not bugs – can be causing the oozing sap. For example, look at the high temperatures the past few of weeks: April 24 – 64 degrees; May 2 – 97    degrees; May 6 – 76 degrees; and forecast for Wednesday – 104 degrees. Talk about yo-yoing temperatures.
Of course, gumming on the hull can be attributed to stink bugs or leaf-footed bugs. Here’s what University of California IPM says about these pests:

Oozing can come from bug damage or nature.
Here is what an egg mass from leaffooted bugs looks like.
·         The leaffooted bug overwinters in the adult stage in aggregations in orchards, or near orchards on native host plants, from which it migrates into orchards in March or early April in search of nuts on which to feed. Varieties with softer shells such as Fritz, Sonora,  Monterey and Peerless are more susceptible to bug damage for a longer period during the season.
·         Stink bug damage is more common in May and June.  Another way to distinguish damage, considering that symptoms are so similar, is to find the actual bugs or their egg masses. 

How do you tell if the gumming is bug or weather related? Jenna says growers should cut a cross-section across the damaged area to look for puncture marks from the bug’s mouth to confirm the gumming is caused by pests instead of Mother Nature. In addition, spotting masses of eggs and damaged nuts are the most practical way to see if there are leaffooted plant bugs or stink bugs around.

Meanwhile, field scout Carlos Silva reports pest populations have been low in alfalfa. Growers are waiting for their crop to grow a little more before moving ahead with the second cutting of the season.  It still early to determine if there will be a third cutting due to the drought.

In cotton, the seedlings are doing well and developing the first true leaf. Soon, we’ll start seeing plant development.

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