Fusarium Dieback / Polyphagous Shot Hole Borer

Recently  a new beetle/fungal complex was detected on avocado and other host plants in Los Angeles, Orange and San Bernardino Counties. The two fungal species are  Fusarium euwallaceae and Graphium sp., which form a symbiotic relationship with a recently discovered beetle that is commonly known as the polyphagous shot hole borer (PSHB, Euwallacea sp.)

Together, they cause the disease Fusarium dieback (FD). When the beetle burrows into the tree, it inoculates the host plant with the fungus (Fig. D), which is carried in its mouthparts in a structure called mycangia.

The fungus attacks the vascular tissue of the tree, blocking the transport of water and nutrients from the roots to the rest of the tree, and eventually causing branch dieback. The beetle larvae live in galleries within the tree and feed on the fungus.

FD has been observed on more than 110 different plant species in California, including many species common in urban landscapes and on such agriculturally important species as avocado, olive and persimmon.

 Symptoms:  Each host species shows different symptoms depending on the response to infection. Sycamore, box elder, maple, red willow, and castor bean are good trees to search for signs and symptoms of the beetle, as it tends to prefer to infest these hosts first. Depending on the tree species attacked, PSHB injury can be identified either by staining, gumming, or a white-sugar exudate on the outer bark in association with a single beetle entry hole.

The vector beetle:  An exotic ambrosia beetle (Euwallacea sp.) is very small and hard to see. At the advanced stage of infestation, there are often many entry/exit holes on the tree (Fig. E-F). Females are black and about 1.8 – 2.5 mm (0.07-0.1 inch) long (Fig. A-B (right)); males are brown colored and about 1.5 mm (0.05 inch) long (Fig. B ((left)). The entry/exit hole is about 0.85 mm (0.033 inch).

What to do:

  • Look for a single entry/exit hole surrounded by wet discoloration of the outer bark
  • Scrape off the bark layer around the infected area to look for brown discolored necrosis caused by the fungus.
  • Follow the gallery to look for the beetle (may or may not be present).
  • Avoid movement of infested firewood and chipping material out of infested area.
  • Look for other hosts (Castor bean, sycamore, maple, coast live oak, goldenrain, liquidambar) showing symptoms of the beetle/disease.
  • Sterilize tools to prevent to spread of the disease with either 25% household bleach, Lysol® cleaning solution, or 70% ethyl alcohol.

Who to contact if you find the problem: If you suspect that you have found this beetle or seen symptoms of the Fusarium dieback on your tree please contact either your local farm advisor, pest control advisor, county Ag Commissioner office or Dr. Akif Eskalen by either phone 951-827-3499 or email at akif.eskalen@ucr.edu.

For more information visit www.eskalenlab,ucr.edu

Housing Market Recovery Helps Timber Producers

Source: Steve Adler; Ag Alert

Home construction in California is on the upswing as the housing sector slowly recovers from the dramatic downturn of the recession that saw home prices and new construction plummet.

Going hand in hand with the increase in home building is the demand for lumber for framing, moldings, doors, fences and other uses. California timber producers say they welcome the increased demand for lumber, but are held back by the regulatory climate in the state that cuts into their bottom line.

As a result of added costs and restrictions on timber harvest, California forestry owners say they have difficulty competing with their counterparts in Washington, Oregon and British Columbia who work in a more business-friendly climate.

An estimated two-thirds of the building materials utilized in California comes from the Pacific Northwest and Canada’s westernmost province.

“Lumber production in California has dramatically fallen off from where we were a couple decades ago,” said Mark Pawlicki, director of corporate affairs for Sierra Pacific Industries in Anderson. “We are harvesting around 1.4 billion board-feet of timber now in California, and that is less than half of what it used to be. A lot of the fallout has been because of the reduction in sales of timber in national forests. It is a combination of regulations involved and a philosophical change within the U.S. Forest Service that occurred back the 1990s.”

Timber owner Peter Bradford of Booneville, who serves as board liaison to the California Farm Bureau Federation Forestry Advisory Committee, said the high cost of regulations “adds a substantial amount” to the price of California timber.

“We are very over-regulated when compared to Washington, Oregon or British Columbia,” Bradford said. “There is a lot of material that comes in from Oregon and Washington because the cost to get a harvest plan to log the trees is easier and much less costly than it is here. It is time, paperwork and cost here in California.”

Despite these challenges, timber owners in California say they are more optimistic than they were a few years ago, when the market for timber had decreased significantly.

“Prices right now aren’t the greatest, but they are better than they were five years ago. For some of the redwood that we are selling this summer, we’ve been given a price of around $900 for 1,000 board-feet. Back in the heyday of the late 1990s, we were receiving $1,500 for that same amount of lumber,” Bradford said.

Pawlicki noted that lumber is a cyclical market.

“As everyone knows, housing construction has been way off in recent years, but it has been gradually coming back. We have seen improvements in U.S. housing construction and along with it improvements in lumber pricing,” he said.

There are currently about 30 lumber mills in California, a decline of 80 mills since the 1990s.

“With the downturn that we experienced in lumber demand, a lot of sawmills closed in California and we are roughly in balance now with supply and demand,” Pawlicki said. “As demand goes up, we expect to see some pricing increases for lumber—not dramatic, but nevertheless steady. And that helps us to maintain our industry here in California.”

Producing more lumber in California to meet the state’s demand, he said, would require “some significant changes in the regulatory world.”

“Folks are not too inclined to build a new sawmill in this state with the regulatory environment that we have,” he said.

Another concern is the tight labor supply, particularly for employees who are experienced in timber harvest and millwork.

“Labor is a tremendous issue in the timber industry right now, trying to get people who are able to do the work,” Bradford said. “This is frequently something you are born into and you know how to do it.”

The labor shortage is felt most acutely in the mills, according to Pawlicki.

“We are experiencing some difficulty filling jobs, particularly millwrights and technical folks in our mills. These mills now are very technical and computerized systems for sawing lumber. It requires a different skill-set than what was required in the past,” he said.

The California drought creates concerns for foresters for several reasons, including increased fire danger and a slowdown in tree growth that corresponds to the lack of water for the trees’ root systems.

“The drought stresses the trees and we will see some tree die-off. We are concerned that we may lose a lot of trees to drought—and when that happens, insect infestations occur and that kills even more trees, and this creates an increased concern for catastrophic wildfires,” Pawlicki said.

Bradford said wildfire concerns also build because of the problems that small landowners face in trying to harvest their timber.

“The amount of environmental review that they have to go through to get a timber harvest permit and the cost to get that review done, with the market value of timber now, makes it economically undesirable. As a result, some of these properties are being sold for home sites. With this increased population comes an increase in the fire danger,” he said.

Bradford said he has seen a buildup in understory in the forests—shrubs, bushes and grasses—that has created dangerous fire conditions.

“That is the worst part of it. The other thing, of course, is that without the normal amount of rainfall, the trees won’t grow as fast as usual. But that is something that is pretty hard to measure,” he said.

Despite the ongoing challenges facing the timber business, Pawlicki noted some positive signs.

“We are optimistic that the market is going to improve domestically. We are seeing some improvements in operating conditions in California, and we are seeing some improvements in the legislative and regulatory front that have helped us,” he said.