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This is a call to prepare for pest invasions with an eye to proactive biocontrol written by Mark Hoddle in a recently published article in the journal BioControl:

https://link.springer.com/article/10.1007/s10526-023-10206-5

A new  paradigm: proactive biological control of invasive insect pests

Invasive insect pests are a significant and accelerating threat to agricultural productivity, they degrade wilderness areas, and reduce quality of life in urban zones. Introduction biological control, the introduction, release, and establishment of host-specific efficacious natural enemies, is an effective management tool for permanently suppressing invasive pest populations over vast areas, often to levels that may no longer cause economic or environmental damage. However, introduction biological control programs are reactive: they are only initiated after an invasive pest has established, spread, and is causing damage that requires mitigation. Host specificity and host range testing of natural enemies for use in an introduction biological control program against an invasive pest can take years to complete. During this time, the target pest population continues to increase, invades new areas, and inflicts damage.

Proactive biological control research programs identify prior to their establishment pest species that have high invasion potential and are likely to cause economic or environmental damage once established. Natural enemies are selected, screened, and if sufficiently host-specific, approved for release in advance of the anticipated establishment of the target pest. Following detection of the target pest and determination that incipient populations cannot be eradicated, natural enemies already approved for release are liberated into infested areas.

This proactive approach to introduction biological control could significantly reduce project development time post-invasion, thereby lessening opportunities for pest populations to build, spread, and cause damage.

Tamarixia radiata wasp for Asian Citrus control

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.