A new  paradigm: proactive biological control of invasive insect pests

To achieve groundwater sustainability under California's Sustainable Groundwater Management Act, or SGMA, demand management – policies that encourage water conservation – will be necessary, says Ellen Bruno, University of California Cooperative Extension specialist in quantitative policy analysis at UC Berkeley.

A key feature of the state's approach to SGMA is that local groundwater sustainability agencies can develop their own plans for achieving sustainable groundwater use, allowing for local flexibility and experimentation.

Reflecting the open-ended nature of the law, Groundwater Sustainability Plans across the state include a variety of water conservation strategies. Many, but not all, GSPs include tools such as allocations, taxes or fees, pumping restrictions, or efficiency incentives. Understanding these policy choices is important because they will influence the economic costs of SGMA.

To help people understand groundwater sustainability plans for their area, Bruno and UC Berkeley Ph.D. student Arthur R. Wardle have created a database. They record and explain the demand management proposals made in the state's 118 submitted groundwater sustainability plans and make these data publicly available in a new online platform called the SGMA Demand Management Action Database (SGMA-DMAD.com).

“The site allows for bulk download of the data we collected,” Wardle said. “Users can also locate a specific groundwater sustainability agency on a map of California to see what demand management strategies that agency is proposing.”

The Demand Management Action Database is the first easily navigated collection of the demand management strategies being proposed across California.

Many GSPs include over 1,000 pages, reflecting the many criteria they are required to satisfy. Among these pages are discussions of hydrogeologic features of the relevant groundwater subbasin, projections of future water demands and supplies, water budgets and other information necessary for the development of an effective management plan. Only one small section of the GSP, usually taking up only about a dozen pages, explains the management actions the agency is proposing to achieve sustainability.

“GSPs are an imperfect guide to what will actually happen as groundwater agencies implement SGMA,” Bruno said. “The plans laid out in GSPs are subject to change. However, submitted GSPs are the best publicly available evidence of what steps groundwater sustainability agencies plan to take in meeting their SGMA obligations.”

GSPs often distinguish between plans that will definitely be undertaken and plans that are provisional, subject to external approvals, need for additional funding, or are simply being left in the planning stage due to uncertainty over future water needs. The Demand Management Action Database includes information distinguishing between plans that are or will be implemented, versus those that remain uncertain.

“Some plans are still undergoing review and approval from the state,” Bruno said. “But even for the plans that have been approved, they have until 2040 to actually achieve their sustainability goals – or 2042 for basins not in critical overdraft – so I'm sure there will be adjustments to these proposals over time.”

In evaluating the role of demand management in submitted GSPs, the authors categorized demand management actions into a few broad categories – allocations, taxes/fees, pumping restrictions and efficiency incentives – each with a good deal of variation within them.

For each GSP, the Demand Management Action Database shows whether some policy fitting into each of these buckets is discussed in the GSP, along with details and page numbers for people wanting to know more about how a specific GSP is implementing each policy.

For those wanting to conduct their own analysis, the site also includes a download button enabling the entire database to be accessed at once. This data is free to use with proper citation.

Anyone interested in SGMA governance is invited to explore the site and send questions, comments or concerns to Arthur R. Wardle at arw@berkeley.edu.

So what causes these wounds on leaves and fruit on lemons? Corky, sunken  blisters on the leaves. Small divots in the fruit. Some of the spots had halos around them, but most not. That would indicate an infection of some sort. It was showing up in a large orchard near Santa Paula.The growers indicated that maybe 20% of the fruit was affected.

Insects? None. Disease? Not really. More damage was on the fruit than leaves, but what would cause what looked like mechanical damage like this? Outside fruit and mostly on the outside of the outside fruit. Wind poking stems? Frost heave? Hail?

Looking round the area at other orchards, other owners, other management practices, old trees and new. The whole area had the problem and it was only on lemons. It wasn't on opuntia cactus or some nearby avocados, oleanders, or roses. But it was something real and it was something that had happened in that area. Rain. High humidity. Things we don't normally see here in the summer time. And what do we get - Edema.  Cell Burst.  Mesophyll Collapse.

Edema may be caused by any agent that stimulates an abnormal increase in the size and number of a group of inner cells. Edema can be induced by (1) spraying with some chemicals such as ammoniacal copper carbonate in an oil emulsion, (2) injuries resulting from wind-blown sand particles and sucking insects, (3) high light intensity, and (4) accumulation of water in the intercellular spaces.

The most common cause of edema is the presence of abundant, warm soil water and a cool, moist atmosphere. Under these conditions the roots absorb water at a rate faster than is lost through transpiration. Excess water accumulates in the leaf, some parenchyma cells enlarge and block the stomatal openings through which water vapor is normally released from the plant; thereby contributing to further water retention in the leaf. If this condition persists, the enlarged cells divide, differentiate a cork cambium, and develop elongate cork cells externally to form a periderm. The rupture of the epidermis by the enlarged inner cells and the periderm account for the raised, crusty appearance of older edema spots and also corky veins.

So what can a lemon grower do? Especially since more rain is forecast for this coming year.

1. Avoid irrigation or watering during cool, overcast humid weather. Irrigate when soils need to be watered. Avoid a fix schedule and when humidities are high.

2. Avoid overfertilizing, especially when the plants are growing slowly, such as during the winter months. Maintain fertility based on a leaf analysis. Avoid low levels of potassium and calcium.

Photo:

Early on, the black spots on the fruit start out as a clear exudate.  The same for the brown spots on the leaves.

Ant Management Workshop

For Citrus, Avocado, Cherimoya, Passion fruit, Dragon fruit Growers

21 September 2023

8:30 – 3, Thursday

Cooperative Extension Ventura County Office

669 County Square Drive, California Room

Ventura, CA 93003-5401

Meeting Registration Link

Workshop Overview: Ants, especially the invasive Argentine ant and the native grey field ant, are serious agricultural pests because they protect sap sucking insects infesting citrus, cherimoyas, grapes, and other perennial tree and vine crops, from their natural enemies. In return for protection, hemipteran pests like Asian citrus psyllid, mealybugs, soft scales, aphids, and whiteflies reward ants with honeydew, a sticky sugar-rich waste product that ants drink and return to nests to feed nest mates. This is an example of a food-for-protection mutualism that is highly disruptive to biological control and IPM programs. This workshop will cover the latest developments in ant monitoring and management and will provide overviews on the benefits of ant control and how reductions in ant densities results in very high levels of biological control of important hemipteran pests.

4.5 "other" DPR CEUs have been applied for.

Workshop Agenda:

Contacts: Ben Faber @ bafaber@ucanr.edu or Hamutahl Cohen @  hcohen@ucanr.edu

Cruising the avocado orchard, checking out the irrigation system

Then Bang!!!!!!! What hit me?????

A little closer look, after clearing some sticky stuff off my head and hair and face and shirt and still not getting it completely off.

And there's the remainder of a spider web with a spider in the center of it (that brown blob near the top right)

And high in the sky there's another spider above my head (that little little dot)

I must have initially hit “signal threads” which alert the spider that I was coming, because just as I took these photos, it had scampered off into hiding in a leaf. I tried to get more close-ups but the spider just did not want to get close. It looked like the an unidentified species of Araneidae family of orb weaver spiders that is common in the Ventura/Santa Barbara area.

They have been common all spring and summer this year. The Year of the Orb Spider, maybe. It's been an unusual year with all the rain and mild weather. They feed on all manner of insects that fly into their webbing – thrips, whiteflies, moths, even hummingbirds have been known to be caught up in orb weaver webbing.

They are usually most active at night and morning, repairing the webbing from the night's catches and other orchard intruders. Their webbing can stretch for several feet between branches, with the web catching portion (where the circular part is most intensive) from 6 – 18 inches.

This year has also seen a flurry of infestation by the Caloptilia avocado leaf roller/miner. Maybe that's why there's been so much more spiders, since there's more food.

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=48887

Whatever the cause of the increased orb spiders is, it's best to thread your way through the orchard with an outstretched branch, used like the wand of a conductor, acting like you know what you are doing.

A study about orb spiders from 1980 in San Diego is available online:

California Avocado Society 1980 Yearbook 64: 153-186 A Study of Neoscona oaxacensis (Araneae: araneidae) in Commercial Avocado Orchards in San Diego County, California Frank Henry Pascoe Candidate for degree of Master of Science in Biology, San Diego State University, San Diego, California.

https://www.avocadosource.com/cas_yearbooks/cas_64_1980/cas_1980_pg_153-186.pdf

 Image: Lea Boyd, Saticoy, CA 2023