Pistachio Male Inflorescences as an Alternative Substrate for the Application of Atoxigenic Strains of .

Aflatoxins are carcinogens mainly produced by and in susceptible crops, including pistachio. The primary inoculum sources of these pathogens are plant debris in the orchard soils. In Californian fields, one approach to controlling aflatoxin contamination is based on releasing the atoxigenic strain of AF36 in inoculated (coated) sorghum grains (AF36 Prevail).

Distribution and incidence of atoxigenic Aspergillus flavus VCG in tree crop orchards in California: A strategy for identifying potential antagonists, the example of almonds.

To identify predominant isolates for potential use as biocontrol agents, Aspergillus flavus isolates collected from soils of almond, pistachio and fig orchard in the Central Valley of California were tested for their membership to 16 atoxigenic vegetative compatibility groups (VCGs), including YV36, the VCG to which AF36, an atoxigenic isolate commercialized in the United States as biopesticide, belongs. A surprisingly large proportion of isolates belonged to YV36 (13.3%, 7.

Community Structure of Aspergillus flavus and A. parasiticus in Major Almond-Producing Areas of California, United States.

Several nut crops, including almond, pistachio, and walnut, can become contaminated with mycotoxins. Of greatest economic significance are aflatoxins, which are mainly produced by members of Aspergillus section Flavi. The distribution of the two sclerotial-size morphotypes of Aspergillus flavus (i.

Evaluation of the Atoxigenic Aspergillus flavus Strain AF36 in Pistachio Orchards.

The atoxigenic strain Aspergillus flavus AF36, which has been extensively used as a biocontrol agent in commercial corn and cotton fields to reduce aflatoxin contamination, was applied in research pistachio orchards from 2002 to 2005 and in commercial pistachio orchards from 2008 to 2011. AF36 was applied as hyphae-colonized steam-sterilized wheat seed (the same product and same application rate as used in cotton fields). In all orchards, applying the wheat-AF36 product substantially increased the proportion of vegetative compatibility group (VCG) YV36, the VCG to which AF36 belongs, within A.

Description of a distinctive aflatoxin-producing strain of Aspergillus nomius that produces submerged sclerotia.

A new distinctive strain of Aspergillus nomius that produces the potent mycotoxins, aflatoxins, is described from pistachio, pecan, and fig orchards in California. Similar to the typical strain of A. nomius (as represented by the ex-type), the O strain produced both B and G aflatoxins but not cyclopiazonic acid, had similar conidial ornamentation, and grew poorly at 42 degrees C.

Fungal Decay of First-Crop and Main-Crop Figs.

Fig cultivars grown in California typically have two crops, although the first crop may be unimportant commercially. The first crop, also known as the breba crop, ripens in late spring and early summer, whereas the main or second crop ripens in late summer. For both cultivars studied, Conadria and Calimyrna, the first-crop figs typically are left in the orchard unharvested.

Ochratoxin production by the Aspergillus ochraceus group and Aspergillus alliaceus.

Ochratoxin A is a toxic and carcinogenic fungal secondary metabolite; its presence in foods is increasingly regulated. Various fungi are known to produce ochratoxins, but it is not known which species produce ochratoxins consistently and which species cause ochratoxin contamination of various crops. We isolated fungi in the Aspergillus ochraceus group (section Circumdati) and Aspergillus alliaceus from tree nut orchards, nuts, and figs in California.

Relationship Between Shell Discoloration of Pistachio Nuts and Incidence of Fungal Decay and Insect Infestation.

Shell discoloration of pistachio (Pistacia vera) nuts collected from commercial orchards and processing plants was related to fungal decay and insect infestation of the kernel. Nuts with ruptured hulls (early split nuts and nuts with cracked hulls) varied considerably in the amount of shell discoloration, ranging from none to extensive. For both types of hull rupture, as shell discoloration increased, kernel decay also increased.

Production of Bright Greenish Yellow Fluorescence in Figs Infected by Aspergillus Species in California Orchards.

The relationship of bright greenish yellow fluorescence (BGYF) of dried figs under longwave UV light to colonization by Aspergillus fungi was determined. BGYF in naturally infected figs was associated with decay by only four fungal species: the aflatoxin-producing species Aspergillus flavus (both L and S strains) and A. parasiticus, and the aflatoxin nonproducers A.