Desert vegetable crops appear to be skating by just fine for now — weather has been moderate; insect pressure has thus far been nothing unusual. However, melon growers are still facing a smoking gun when it comes to cucurbit yellow stunting disorder virus (CYSDV).
“Worm pressure was high for several weeks, but appears to be subsiding now, since temperatures have modified somewhat,” says Eric Natwick, University of California Imperial County Cooperative Extension farm advisor/entomologist. “There have been plenty of whiteflies as usual, but nothing we can't handle, except for the CYSDV transmission to melons. CYSDV has been widespread again this fall by whiteflies, but it’s too early to make an overall assessment of possible losses to melon growers.”
The whitefly-vectored threat did change the cropping mix this year, according to Natwick. “No squash was planted due to CYSDV, squash leaf curl virus (SLCV) and cucurbit leaf crumple geminivirus (CuLCrV),” he says.
Thrips and aphid pressure in the Yuma area is typical, although moderate weather has contributed to some higher-than-normal populations.
“Insect pressure in general is light, relative to previous years,” says John Palumbo, University of Arizona 3ntomologist at Yuma. “Thrips seem to be heavier than normal for this time of year. That’s probably because PCAs are able to stretch out their worm sprays due to cooler weather and subsequently lighter pressure.
“Temperatures are also conducive to thrips buildup. We have seen some aphids starting to show up on cole crops —probably due to heavy winds blowing in from the north. Again, weather conditions have been favorable for their population growth.”