The emergence cycle of captured walnut twig beetles (WTB) is being documented at LREC. The tiny beetles, in addition to a suite of other log-dwelling insects (including their parasitoids), emerge nearly year-round from infested walnut logs that are housed in outdoor enclosures. The insects are collected weekly, and then sorted, sexed, and counted. In 2013, WTB emerged from March-September, with peak emergence in mid-late June. In 2014, peak WTB emergence peak occurred in May-June, and emergence counts are falling off rapidly now that it is midsummer. One notable week's collection was May 13-20, with 1940 emerged WTB from one of the six emergence chambers.
Dr. Elizabeth Fichtner (Farm Advisor, Tulare UCCE) has recently acquired Yelena Martinez, a participant in the College of Sequoias SURGE (Student Undergraduate Research Group Experience) program, to assist Katie Wilson (UCCE Tulare) and Therese Kapaun (LREC) with the staggering number of weekly counts during the peak season. This photo shows Yelena viewing insects under a dissecting microscope and separating the different species into containers. Katie and Therese will continue to monitor and count emergences for at least the next twelve months.
WTB has been recently found to be associated with Thousand Cankers Disease, a fungal pathogen of several walnut species in North America. The pathogen was also recently reported on black walnut in Italy. More information on the disease, as well as the beetle can be found at:
UCCE In a Nutshell Newsletter Tulare County (pages 5-7)
Dr. Carol Lovatt (UC Riverside, Dept. of Botany and Plant Science) and Elizabeth Fichtner (UC Cooperative Extension Tulare County) continue olive research at Lindcove REC. A foliar application of plant growth regulator treatments in combination with urea was applied to mature olive trees this week to determine the potential value of these products to reduce or eliminate the alternate bearing cycle in olives.
Toan Khuong is seen here applying the foliar spray. Toan is a Staff Research Associate in Dr. Lovatt's lab at UC Riverside.
In March we budded more than 2000 citrus trees with various scions for upcoming research projects. May is a great time of year to watch the phenomenal growth of vegetation in a greenhouse. Vigorous varieties such as lemons have been putting on up to five inches of new growth each week, while navel and mandarin varieties are growing well although not as fast.
This photo shows what newly pushing buds look like, with the upper rootstock tops cut off and bent over at an angle. After the new growth of the scion reaches six inches or more, the remaining rootstock above the scion is removed completely so that the scion becomes the dominant trunk for photosynthetic activity and nutrient movement.
Sixty young avocado trees were recently planted in the avocado block at Lindcove REC. Dr. Mary Lu Arpaia (UCANR, CE Subtropical Horticulturist) is introducing new varieties that may show promise for growers in the San Joaquin Valley. Commercial avocado is typically grown in temperate and coastal climatic zones, and is generally intolerant of the long hot summers and occasional freezing spells of this area.
Lindcove is one of four sites chosen for this trial, which aims to evaluate new varieties of commercial potential. Trees will be evaluated for vigor, flowering characteristics, and tolerance to cold and heat. Fruit will be evaluated for yield, maturity date, and postharvest quality.
The trial began in 2011 with 45 trees of three varieties, and new plantings each year have increased the size of the block to 222 trees of eleven varieties. Dr. Arpaia's project is funded by the California Avocado Commission.
- Author: Elizabeth E Grafton-Cardwell
The Citrus Production Manual is published!
For the month of April the price is reduced from $75 to $60! This is the first citrus manual in more than 20 years to cover all the major topics of citrus production including planting, horticulture, pest management and post harvest issues. It is a wonderful resource for all citrus producers and pest managers.
To order a copy, go to the UC Ag and Natural Resources catalog http://anrcatalog.ucanr.edu/ and type in publication 3539 or the search term 'citrus production manual' or call 1-800-994-8849.
Better yet, if you buy both the Citrus Production Manual and the IPM for citrus manual (pub 3539Promo) the combined price is only $85 - a savings of $30!