Re: [compost_tea] Aphid control by Fungi?? (was Asian rust)

From: Scott Alexander <daylily_at_bigpond.com>
Date: Fri, 26 Nov 2004 06:42:55 +1000


  Hello Scott

  If the aphids died after the CT application, perhaps leaf micro-climate c=
hanged to the extent that it was no longer viable for that species of aphid=
s, so not a direct correlation for ct=aphid death, complex yes, provable =
to whom for what value derived?

  Hello Terence,
  I've observed fungi destroying huge infestations of the daylily aphid in =
the past. Although a Queensland University entomologist (and a daylily love=
r) visited my nursery to observe this he never wrote a paper on it. In 1988=
 I had trailed Safer's Insecticidal Soap spray on a 100 square metre plot a=
nd left the remaining 2 acres unsprayed. The effect of the soap spray was i=
mmediate but within two weeks, something had killed most of the aphids on e=
very plant on the remaining area, hence the visit from the entomologist to =
observe this phenomenon.

  Since moving to a new property and (coincidentally?) began using compost =
tea, aphids in plague proportions have never been observed. Elaine asked me=
 to trial my CT on aphids and i think we proved a connection.

  Readers may find the extract from this website of interest
  http://www.ent.iastate.edu/entsoc/ncb98/prog/abs/d-111.html

  D-111 INTERFERENCE OF POTATO LATE BLIGHT FUNGICIDES WITH FUNGAL ENTOMOPAT=
HOGENS OF GREEN PEACH APHID. J. Ruano-Rossil, D. W. Ragsdale, and E. B. Rad=
cliffe, Department of Entomology, University of Minnesota, 1980 Folwell Ave=
nue, Hodson Hall, Saint Paul, MN 55108

  Since 1992, the predominance of metalaxyl-insensitive strains of Phytopht=
hora infestans (US8/A2 mating type), the pathogen that causes late blight, =
has necessitated that potatoes receive 8-16 applications of protectant fung=
icides compared to the 2-4 applications formerly required. Many potato grow=
ers have also experienced outbreaks of green peach aphid, Myzus persicae (S=
ulzer), of unprecedented severity leading in many cases to premature plant =
death. Entomopathogenic fungi can keep green peach aphid populations in che=
ck, especially when aphid populations are high and environmental conditions=
 are conducive to fungal dissemination and germination.

  Scott Alexander










Received on Thu Nov 25 2004 - 23:16:15 EST

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