Subtropical Fruit Crops Research & Education
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Subtropical Fruit Crops Research & Education

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Italian White Snail, Yum. Here it comes again

Sometimes an invasive pest takes a while to become invasive. The Invasive Species Council of California defines an invasive species as “non-native organisms which cause economic or environmental harm.” So, until a species not originally from the area actually causes harm, it doesn't get the title of invasive.

Take the Italian white snail, also known as the white garden snail. In San Diego, it caused extensive damage to agricultural plants in the early 1900s but was considered eradicated after a massive control program in the 1920s. However, it was found again in San Diego County in the 1980s but it did not damage agricultural crops or gardens. Instead the snails lived off of weeds in neglected fields. Now it appears to be moving slowly from these fields to fruit tree orchards and avocado groves as well as landscapes. The Italian white snail feeds on decaying organic matter and living plants, damaging leaves, flowers, and fruit. Another fear is it being found in cut flower growing areas or in nurseries where it could become an export issue.

White or light tan, the Italian white snail is about the size of a dime or nickel when fully grown. It may or may not have brown markings on the outside of the shell. The inside shell color near the opening is light colored (compared to the milk snail, which looks similar but has a dark inside shell). Italian white snails are most noticeable during the day and when it is hot, because the snails climb up on fence posts, walls, weeds and other vegetation and congregate in large numbers.

In California, the Italian white snail is only officially found in San Diego County. However, it could easily move to new areas because of its small size, which makes it hard to detect, and tendency to attach to many kinds of surfaces such as truck beds. Also, because land snails are hermaphroditic—each snail has both male and female reproductive organs—it only takes any two snails to reproduce!

Californians can help in the fight against invasive species by learning and participating during California Invasive Species Action Week, June 2–10.

Posted on Friday, June 8, 2018 at 10:50 AM
  • Author: Tunnyalee Martin and Cheryl Wilen
Tags: brwon (1), invasiive (1), pests (23), snails (3), white snail (1)

Irrigation Emitters - Do They Operate as Advertized?

The Irrigation Training & Research Center (ITRC) of Cal Poly San Luis Obispo tested 28 different pressure-compensating models of microirrigation emitting devices from a total of nine manufacturers in order to compare independent laboratory testing with manufacturer specifications.

The test results indicate that:

The majority of ~0.5 gallon-per-hour emitters (drippers), regardless of manufacturer exhibited:

  1. Good uniformity of manufacturer

  2. Had excellent response to pressure variation

  3. Had consistent flow rates within the nominal operating pressure range 

    But that the percentage of well-performing products decreased as the designed flow rate increased. Many of the emitters designated as microsprinklers or sprayers, although pressure compensating did not compensate at the normal operating pressures. Often the pressure compensating feature did not start performing until much higher pressures were achieved. Often this occurred when clogging occurred and this clogging often occurred where the pressure diaphragm was located and was not performing. Sediment would get in back of the diaphragm.  Effectively the emitters were not pressure compensating. The testing procedure of numerous medium and high flow models also found individual pieces were found to be defective. These faulty emitters had a measurable effect on the evaluation for those models.

    Read more at:

    An example of the comparisons that ITRC canbee seen here of their results, compared to the manufacturers' values:
Posted on Wednesday, June 6, 2018 at 12:07 PM

Upcoming Citrus Meetings

Citrus Research Board Announces

        2018 Citrus Grower

             Seminar Series


The Citrus Research Board (CRB) is proud to announce the return of the Citrus Grower Seminar Series, co-produced by the University of California Cooperative Extension (UCCE). Three different meeting dates and locations will give growers from different regions the opportunity to attend.

The FREE half-day seminars start at 8:30 AM and are expected to end at 12:00 PM. Registration will begin at 7:30 AM.

CLICK HERE to register for the seminars.

CLICK HERE to view event flyer (including guest speakers).

Continuing Education (CE) Units have been applied for and are pending approval through the California Department of Pesticide Regulation for license categories PCA, QAL and QAC.  Certified Crop Adviser (CCA) Units have also been applied for and are pending approval.

Posted on Tuesday, June 5, 2018 at 9:58 AM
Tags: citrus meetings (1), crb (1)

Talkin Borers

UC ANR Integrated Pest Management Program

A sugar volcano is one symptom that shows your avocado tree might be infected with Fusarium dieback, a fungi spread by a beetle called the shothole borer. But what you might see if your tree is being attacked by shothole borer, varies among the different kinds of tree hosts. The symptoms—staining, sugary exudate, gumming and beetle frass—are often noticed before the tiny beetles (1.5–2.5 mm) are found.

As its name suggests, these beetles bore into trees. Near or beneath the symptoms, you might notice the beetle's entry and exit holes into the tree. The female tunnels into trees forming galleries, where she lays her eggs. Once grown, the sibling beetles mate with each other so that females leaving the tree to start their own galleries are already pregnant. Males do not fly and stay in the host tree.

Shothole borers have a special structure in their mouth where they carry two or three kinds of their own novel symbiotic fungi. Shothole borers grow these fungi in their tree galleries. It's these fungi that cause Fusarium dieback disease, which interrupts the transportation of water and nutrients in the host tree. Advanced fungal infections will eventually lead to branch dieback.

Early detection of infestations and removal of the infested branches will help reduce beetle numbers and therefore, also reduce the spread of the fungus.

  • Chip infested wood onsite to a size of one inch or smaller. If the branch is too large to chip, solarize them under a clear tarp for several months
  • Avoid movement of infested firewood and chipping material out of infested area

Avocado is one tree host. Shothole borers successfully lay eggs and grow fungi in many tree hosts, with some of these trees susceptible to the Fusarium dieback disease. For more information about tree host species, where the shothole borer is in California, and what symptoms look like in other tree hosts, visit the UC Riverside Eskalen Lab website.

Californians can help in the fight against invasive species by learning and participating during California Invasive Species Action Week, June 2–10.

During the week, spend your lunch with us learning the latest about invasive tree killing pests, aquatic nasties like quagga mussels and nutria, and how the invasive weed/wildfire cycle is altering our ecosystems!


Content in this post taken from the UC IPM Avocado Pest Management Guidelines. Faber BA, Willen CA, Eskalen A, Morse JG, Hanson B, Hoddle MS. Revised continuously. UC IPM Pest Management Guidelines Avocado. UC ANR Publication 3436. Oakland, CA.

And more about Shot Hole Borers

Posted on Monday, June 4, 2018 at 10:45 AM
  • Author: Tunyalee Martin
Tags: avocado (231), Invasive (2), Ishb (3), KSHB (16), kuroshio (6), polyphagous (5), PSHB (30), shot hole borer (6)

Raspberry Tunnel Mangement Workshop

Stormwater and Sediment Management in Plasticulture Tunnels

13 June, Wednesday 8:30 AM-NOON
At UC Hansen Agricultural Center at Santa Paula
(from hwy 126 exit Briggs, the entrance gate is ~1000 ft on the left on Briggs road)
8:30 Registration, (interpretation into Spanish provided for the program).
9:00 Update on Agricultural Conditional Waiver and nutrient management requirements
9:20 Establishment of Best Management Practices (BMPs) in post rows in raspberry plasticulture tunnels
9:30 Effect of BMPs on nitrogen
9:50 Effect of BMPS on phosphorus, turbidity of runoff and sediment movement
10:10 Effect of BMPs on weeds
10:20 Costs of the tested BMPs
10:30 Look at treatments, demo of Polyacrylamide, questions and survey
11:00 Lunch

VCAILG (Ventura County Ag Irrigated land) credits have been requested from RWQCB.

If you require special arrangements, translation into Spanish or have further questions, please contact Oleg Daugovish at UCCE –Ventura: (805) 645-1454 or

El Manejo de Aguas Pluviales y Sedimentos en los Túneles de Plasticultura
13 de Junio, Miércoles de 8:30 al Mediodía
En el UC Hansen Agricultural Center de Santa Paula
(de la 126 se toma la salida Briggs, la puerta de entrada queda a 1000 pies a la izquierda en la Briggs road)
8:30 Registración, (interpretación en español disponible) .
9:00 Actualización de la Exención Condicional Agrícola y los requisitos para el manejo de
9:20 Establecimiento de Mejores Prácticas de Gestión (BMP) en las filas con postes en los túneles de plasticultura de la frambuesa
9:30 Efecto de estas prácticas (BMP) sobre el nitrógeno
9:50 Efecto de estas prácticas (BMP) sobre el fósforo, turbidez de la escorrentía y
movimiento de los sedimentos.
10:10 El efecto de estas prácticas (BMP) sobre la maleza.
10:20 Costos de estas prácticas que ya se han experimentado
10:30 Vistazo a los tratamientos, demostración de la poliacrilamida, preguntas y encuesta
11:00 Lonche
• Se han solicitado créditos VCAILG al RWQCB.
Si usted requiere arreglos especiales, traducción al español o tiene otras preguntas, favor de comunicarse con Oleg Daugovish a UCCE –Ventura: (805) 645-1454 o

Posted on Monday, June 4, 2018 at 9:46 AM

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