- Author: Ben Faber
The latest edition of Topics in Subtropics newsletter is out, Elizabeth Fichtner as editor. Read on.
TOPICS IN THIS ISSUE:
-
Why has California red scale been so difficult to control?
-
Navel Orange Nitrogen Fertilization
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Recent Advances in Understanding the History of Olive Domestication
- Upcoming UC Olive Center Events
- Author: Ben Faber
It's that time of year for a riot of aphids on new growth cheeseweed (malva) and wild radish and with that food source to see ladybird beetles go to town, chowing down. There's ladybugs in both their larval and adult stages doing the feeding. Some of the larvae look like mealybugs which is a food source that they mimic and also feed on. The mealybug destroyers was introduced from Australia at the turn of the 20th century to fight citrus mealybug and when there is no disruption, they are effective at keeping the population down. Another mealybug mimic is the dusky ladybird which also feeds on scales, aphids and mealy bugs. These are generalist predators, even cannibalizing their own, when other food sources are not present. The dusky has not been common in the Ventura area, but recently, PCA Jane Delahoyde spotted one. As our weather changes, we are bound to see other insects and invertebrates move into the area.
Check out this University of Florida ladybug website:
http://entnemdept.ufl.edu/creatures/beneficial/lady_beetles.htm
Mealybug-like larval stage surrounded by aphid food (above) and adult (below)
- Author: Ben Faber
Chlorpyrifos (Lorsban) is a pesticide long used in citrus along with many other crops. It is an organophosphate that has value partly because it is persistent, which is also one of its drawbacks. One of its uses is to control ant species that "farm" such pests as mealybug, aphids and scales. Many organophosphate materials have been removed from the market and their use in residential settings has been severely curtailed. New restrictive uses are now in place for this material in agriculture and an informational meeting is being held in September for citrus growers on what approaches to take with these restrictions. During the meeting a workshop on ant identification and management will be offered.
Ventura County Breakfast IPM Meeting
Citrus IPM and Chlorpyrifos Regulatory Update
September 16, 2015 8:00 AM – Noon
Hot Breakfast and Coffee at 8:00 AM
Hansen Research Center
14292 W Telegraph Rd (parking accessed from Briggs Road)
Santa Paula, CA 93060
Registration and Hot Breakfast at 8:00 AM
Meeting Runs 8:30 AM until Noon
Time |
Topics |
Org/Speaker |
Minutes |
8:00 AM |
|
Group |
- |
8:30 AM |
|
Ben Faber, UCCE Farm Advisor Ventura County |
15 |
8:45 AM |
|
Peter B. Goodell and Lori Berger, UC Statewide IPM Program |
45 |
9:30 AM |
|
Dennis Chessman or NRCS Representative or UC Statewide IPM Program Personnel |
15 |
9:45 AM |
|
Beth Grafton-Cardwell, UCCE, Lindcove REC |
30 |
10:15 AM |
BREAK |
BREAK |
15 |
10:30 AM |
|
Kris Tollerup, Area IPM Advisor, Kearney REC |
30 |
11:00 AM |
|
Mark Robertson and/or Randy Segawa, CDPR |
20 |
11:20 AM |
|
Representative of the Ventura County Ag Commissioner Office |
10 |
11:30 AM |
|
“Local Leadership”
UCCE/ PCA/Grower/ Crop Team Leader panel
|
30 |
Meeting Adjourns at Noon |
CDPR Continuing Education Units Applied for: 3.0 hours (1.0 Laws/ 2.0 Other)
Hot Breakfast Courtesy of Citrus Research Board
- Author: Ben Faber
It never got very cold this winter in spite of the freeze we had at the turn of the new year. Insects that are normally knocked back by cold weather such as scales and the formidable Asian Citrus Psyllid continued on very well, thank you. Along the coast we have have had a major issue with red scale in lemons, which normally is in pretty good biological control.
California red scale and yellow scale are armored scales that are distributed throughout the citrus-growing regions of the state except in parts of the Coachella Valley where they are under an eradication program. The two species are difficult to distinguish by appearance. Yellow scale, however, is rarely found on mature wood of the tree whereas California red scale can be found on the wood as well as on fruit and leaves. Biologies and management tactics for California red scale and yellow scale are similar, but yellow scale is more easily controlled by natural enemies and, thus, less commonly found.
Female scales have a roundish cover, about the size of the blunt end of a nail. The cover is firmly attached to the leaf, wood, or fruit substrate when the scales are molting or reproducing; they remain under this cover throughout their life. When mature, they produce 100 to 150 crawlers.
Crawlers hatch and emerge from under the female cover at a rate of two to three per day. Crawlers move around to find a suitable place to settle and can be spread about by wind, birds, or picking crews. They settle in small depressions on twigs, fruits, or leaves and start feeding; soon after, a circular, waxy cover forms over their body. Midway through the second instar, females and males begin to develop differently. Males form an elongated cover while the female cover remains circular. The female molts twice, developing a concentric ring in the center of the waxy covering each time.
Adult male scales are small, two-winged insects that emerge from the elongated scale covers after four molts. They live about 6 hours and their sole purpose is to mate. The number of male flights, along with the number of generations per year for this insect varies according to the growing region in the state and the weather but is generally about 4 flights per year.
Oils can be effective against California red scale if coverage is thorough. They also have the advantage of being relatively less damaging to natural enemy populations than other insecticides. However, special care must be taken to avoid applying dilute applications of oil at times when it can damage fruit and leaves or reduce populations of natural enemies. In some cases, though, growers have had to resort to more harsh chemicals such as chlorpyrifos.
- Author: Ben Faber
Jane Delahoyde, a PCA here in Ventura, recently found an unusual scale in lemon here. It is barnacle scale with a typically long Latin name - Ceroplastes cirripediformis. It is unlikely to be any worse than other scales, but it's something to keep our eyes on. This is one of the soft scales, often called wax scales because of the wax they produce. It turns out that this has been described as being in Southern California for years, but some years they are just more present. For more on "Wax" scales see the Texas A&M site
https://insects.tamu.edu/fieldguide/aimg110.html
or our UC IPM website
http://ucipm.ucdavis.edu/PMG/PESTNOTES/pn7408.html
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