So what does cheap natural gas do for California berry growers?  Not a lot apparently, if one extrapolates from an excellent article written by Colin Carter and Kevin Novan and recently released by the Giannini Foundation of Agricultural Economics titled “Shale Gas Boom: Implications for California Agriculture.”

http://giannini.ucop.edu/media/are-update/files/articles/V16N3_1_1.pdf

As most Americans know by now, the ability to access through hydraulic fracturing (known in the common parlance as “fracking”) previously unavailable shale gas resources portends an big shift in the energy dynamics of the United States.

The enormous amounts of shale gas becoming available through fracking in the US has brought about a drop in the price of natural gas nationwide, but this has not been followed with a worldwide drop in natural gas prices.   Natural gas, moved as a gas through pipelines domestically, can only be transported to overseas markets once it has been converted to liquefied natural gas (LNG) at facilities where the gas is turned into liquid form and then pumped into tankers for transit. The current lack of such facilities in the US and subsequent difficulty to get our natural gas to foreign markets has resulted in huge price discrepancies globally, with natural gas prices in the US at approximately $3.30 per thousand cubic feet, at the same time in Europe for example prices are $12 per thousand cubic feet.

This price discrepancy of course presents a real cost advantage for users of energy and natural gas in the US over their overseas competitors.  How much of this price advantage accrues to California berry growers is a question worth examination.

According to the article cited above, only 0.8% of total natural gas consumption in the US occurs in the agricultural sector.  A lot of farm equipment, from tractors to motorized implements to trucks, use gasoline or diesel rather than natural gas.  Obviously, if a lot of this equipment were to be converted to use natural gas there would be some cost advantage, but this is very much a proposition for the long term.

On the other hand, natural gas is the main input in the production of ammonia, which is subsequently converted to the nitrogen fertilizers which are a mainstay of California berry growers, who use anywhere between 160 to 250 lbs of the stuff per acre.  However, fertilizer costs in the berry industry, according the UCCE Cost and Return studies make up only 1% percent of the total cost of production, meaning that price changes in nitrogen fertilizer are not that meaningful in one direction or another to the total cost of running a berry operation.  Furthermore, fertilizer prices are arbitraged internationally, meaning prices tend not to vary too much from country to country, so low fertilizer costs stemming from cheap natural gas feedstock in the USA don’t really translate to much of a cost advantage to local growers anyway.

The other possibility where cheap natural gas prices could confer an advantage to California berry growers would be a reduction in the price of electricity, more than half of which in California is generated from natural gas.  The heavy reliance on irrigation and the use of electricity to get that water out of the ground in California agriculture and the berry business at least superficially points to some savings from reduced energy costs.  However, digging into our latest Cost and Return studies, pumping irrigation water constitutes only about 1.5% percent of the total cost of production of berries.   The gains from cheaper gas and subsequently cheaper electricity will be not that significant in other words.

In conclusion, the increasing amounts of shale gas becoming available through fracking in the US, while offering some possibility of advantage over the long haul in terms of energy inputs for traction and transport, does not appear to give a lot of advantage currently to California berry growers over their foreign competitors in terms of cost of production.

UCCE is sponsoring a meeting on lygus in strawberries to be held April 18.  Four Ph.D. level entomologists (and one fruit guy) will bring together a veritable brain trust in one room to share decades of experience and knowledge in entomology and lygus bugs.

Biology, sampling, cultural, chemical and biological control of lygus will all be discussed.  This is without a doubt a can't miss event for growers, PCA's and anyone else interested in the latest and most in-depth information available on this difficult pest.

Agenda is to be found here:

http://cesantacruz.ucanr.edu/files/163453.pdf

A meeting concerning a phase in of organically produced and certified plant stock (i.e. transplants) in strawberries will take place at the UC Cooperative Extension office at 1432 Freedom Blvd in Watsonville this coming Wednesday, March 20.   The discussion will concern the use of plug plants, a presentation by a producer in the past of organically certified transplants, a clarification of organic plant stock guidance by the USDA and a discussion about anaerobic soil disinfestation work to be done at the nursery level.

The agenda for the meeting is attached can be found at:

http://cesantacruz.ucanr.edu/files/163353.pdf

Introduction:  This blog post is about the very common fungal pathogen of strawberry, powdery mildew.   What follows is a review on the biology and management of this disease. 

Causal Organism: Powdery mildew is caused by the pathogen that historically has been named Sphaerotheca macularis f. sp. fragariae.  However, future scientific publications and other writings will likely use the new name Podosphaera aphanis.  Like most powdery mildew pathogens on other hosts, the majority of the mycelium of this fungus grows on the outside of strawberry leaves and fruit. The masses of mycelium produce spores (conidia) that form in chains, are barrel shaped, whitish to clear (hyaline), and dry (Photo 1). If your vision is sharp, you could be able to see the spores with the unaided eye since powdery mildew conidia are relatively large compared to spores of other fungi. With a hand lens or dissecting microscope, chains of powdery mildew conidia are readily seen.

Symptoms:  Powdery mildew appears as white patches of fluffy mycelium tending to infect the undersides of younger leaves first. If conditions favor the fungus, then the disease advances onto the top  sides of these leaves; in severe cases, powdery mildew moves onto older leaves, petioles, flowers, and fruit.  It is important not to confuse these initial, small white patches of mildew with the waxy white deposits produced by whiteflies during egg laying (Photo 2 and 3).   Mildew infections eventually result in an upward curling of infected leaves.  On some cultivars, such as Camarosa, a brown to purple blotchy discoloration forms on the upper leaf surface (Photo 4) .  Mildew infections of immature fruit result in a small, unripened fruit.  Powdery mildew infections of mature fruit are more obvious due to the white mycelial growth on the surface and the protruding seeds (Photo 6); if such fruit are eaten they can have a distinctive moldy taste.

Disease Cycle:  It is believed that in California the majority of powdery mildew inoculum infecting first year strawberry plantings comes from the leaves or crowns of transplants.  Such transplants are either carrying inoculum on them from the nursery or are already infected prior to being dug.  In addition, second year or volunteer strawberries in the vicinity are likely to be infected with powdery mildew; these established plants provide a second source of spore inoculum that is carried by winds to new plantings.  The powdery mildew fungus produces overwintering, sexual structures called chasmothecia (previously these were called cleistothecia) but these do not commonly form on strawberry grown in California and therefore do not appear to have an important role in disease development.   

Epidemiology: Powdery mildew has certain conditions in which it thrives.  A range of temperatures from 60^o to 80^o (15^o to 26.7^o C) during periods of moderate to high humidity (think fog) are the conditions which are optimum for powdery mildew growth. In addition, the fungus actually does not grow well if leaves are wet with free moisture. So the fungus develops more readily if strawberry foliage is dry.

Management: As fully as possible, an integrated pest management (IPM) approach is suggested when it comes to controlling any strawberry disease. Fungicides are a key IPM component for minimizing powdery mildew infection in strawberries on the Central Coast of California.  There is a wide selection of fungicides available for use on strawberry (http://www.ipm.ucdavis.edu/PMG/r734100711.html). Examples of such products are myclobutanil (Rally), triflumazol (Procure), pyraclostrobin + boscalid (Pristine) and quinoxyfen (Quintec). There are concerns of reduced sensitivity of the pathogen to several classes of these fungicides, but there is no hard evidence of resistance to any of them to date.   It is worth noting that there are no reports of reduced efficacy of sulfur (both as a dust and flowable) despite the many years it has been used against powdery mildew.   Many horticultural oils and insecticidal soaps (for example M-Pede) can also be effective for powdery mildew when applied at a frequency of every 10 to 14 days, but it should be pointed out that frequent applications of these oils or soaps can stress strawberries and reduce plant productivity while also reducing mildew. 

To maximize the efficacy of fungicides used, one should begin applying these materials at the first sign of disease, which on the Central Coast can be as early as February or March and continue as favorable conditions for mildew growth continue.  

Since a large portion of the powdery mildew initially infecting strawberry fields comes from the transplants, growers should make sure they are receiving clean plants. It is standard practice in the California strawberry nursery industry to apply a high number of protectant treatments for powdery mildew, but growers concerned about powdery mildew coming from nursery plants are encouraged to check with their provider to understand mildew management practices. 

Genetic resistance to fungal diseases is an important aspect of disease management.  While there is no complete resistance to powdery mildew in strawberry, there is still a wide range of susceptibility to the disease among the varieties grown in California, a discussion which is beyond the scope of this post. Growers are well advised to be aware of the relative susceptibility for disease in the varieties they are planting, especially if growing in an area known to be problematic for powdery mildew. Also, growers should perhaps avoid planting a very susceptible cultivar adjacent to a second year strawberry field.

The above has been a discussion the biology and management of powdery mildew disease in strawberry.  There are pesticides mentioned for the management of powdery mildew on strawberry in this article.  Before using any of these products, check with your local Agricultural Commissioner’s office and consult product labels for current status of product registration, restrictions and use information.