ABSTRACT
Though in the past Xiphinema americanum has been the most commonly reported dagger nematode in the eastern United States, our studies revealed the presence in Pennsvlvania of a previously unrecognized and unreported species related to X. americanum, Morphometric data and photomicrographs establish the identity of this form as X. rivesi and show expected variations in populations of this species from various locations. Similar data and illustrations are given for X. americanum populations from Pennsylvania and other areas, showing variations and relationships. Xiphinema rivesi is widely distributed in the fruit producing area of south-central Pennsylvania and is also reported herein from raspberry in Vermont and apple in Maryland and New York. This species is frequently found in fruit growing areas of Pennsylvania associated with tomato ringspot virus-induced diseases and is also found associated with corn, bluegrass sod, and alfalfa.
ABSTRACT
Phialospores of verticillium malthousei Ware were atomized onto acclimatized water agar and incubated for 3, 6, 9, 12, and 24 hr at 12 to 36 degrees C intervals. Germination occurred at all temperatures exclusive of 36 degrees C with maximum germination (90-98%) occurring in 24 hr at 12 degrees C, 12 degrees C, 12 HR at 18 degrees C, 9 hr at 24 degrees and 30 degrees C. Volatiles from: 1) horse manure compost colonized by Agaricus bisporus; 2) mycellium impregnated casing (soil); or 3) casing supporting mature and immature mushrooms had no statistically significant effect on spore germination of V. malthousei when measured after 12 hr at 24 degrees C. However, a tendency towards inhibition after 6 and 12 hr at 24 degrees and 12 degrees C, respectively, suggests the inhibition is temperature and time dependent. This dependency was noted with two substrates, colonized compost and casing which supported sporocarps.
