IntRODUctIOn Compared with the rest of the world, the California citrus industry is relatively free of diseases that can impact growers’ profits. Unfortunately, exotic plant pathogens may become well established before they are recognized as such. This is primarily because some of the initial symptoms mimic other diseases, mineral deficiencies, or toxicities. In addition, development of disease...

Bud exudates from 9 poplars showing a range o f resistance to bacterial canker and poplar rust were analyzed by gas chromatography-mass spectrometry and the components o f the bud exudate identified. Those compounds previously reported in the literature to have notable antimicrobial activity were listed and the quantities present in the bud exudates o f the speci­ mens analyzed were compared. N...

Annual postplanting applications of 40.7 kg/ha DBCP (1,2-dibromo-3-chloropropane) controlled Macroposthonia xenoplax (Raski, 1952) deGrisse and Loof, 1965 in peach tree short life sites, reduced bacterial canker incidence from 74% to 6%, and inreased the average life of the trees from 3.9 to 6.8 yr for a 7-yr test period. Hydrated lime at 5.5 kg per planting site reduced bacterial canker incide...

Pitch canker, caused by Gibberella circinata, was discovered in California in 1986. Although initially quite damaging to Monterey pines (Pinus radiata), the severity of pitch canker has moderated in areas where the disease was first observed and some trees appear to have recovered completely. The absence of symptoms on trees that were once severely affected implies they have become more resista...

In 2008, a global production rounding 1,724 and 1,053 million metric tones respectively for walnut and hazelnut has been estimated. Bacterial diseases are threatening these nut crops all over the World. Xhanthomonas arboricola pv. juglandis (Xaj) is the agent of walnut bacteriosis, and has been associated also to brown apical necrosis. Several walnut genotypes have shown a range of tolerance to...

Pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. Light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. Xanthomonas citri subsp. citri is the bacterium responsible ...

For diagnosis of citrus bacterial canker by PCR, an internal standard is employed to ensure the quality of the DNA extraction and that proper requisites exist for the amplification reaction. The ratio of PCR products from the internal standard and bacterial target is used to estimate the initial bacterial concentration in citrus tissues with lesions.