Phosphine and its effect on some common insects in cut flowers
C. Karunaratne, G. A. Moore, R. Jones and R. Ryan
Postharvest Biology and Technology Vol: 10 Issue: 3 Pages: 255-262.
1997
บทคัดย่อ
The most effective fumigant for insect disinfestation of cut flowers is
currently methyl bromide, which will soon be unavailable in several countries.
The toxicity of an alternative fumigant, phosphine (2% PH3 and 98% N2),
was tested at 24°C on adult greenhouse thrips (Heliothrips
haemorrhoidalis), adult aphids (Myzus persicae) and lightbrown apple
moth larvae (LBAM; Epiphyas postvittana). These are commonly found as
insect pests on many cut flower crops. Thrips were exposed to phosphine
concentrations ranging from 20-600
l/l
for 1 or 2 h. All thrips were killed within 18 h of exposure after a treatment
of 300l/l
phosphine for 2 h. Adult aphids and fifth instar LBAM larvae were more
resistant to phosphine, and trials were therefore conducted using higher phosphine
concentrations (> 500 l/l)
combined with atmospheric (0.035%) or elevated (33%) CO2. The most
effective treatment for aphids was 1000l/l
phosphine + 33% CO2 for 4 h, which killed all insects within 36 h of
exposure. Under atmospheric CO2 levels, 92% of aphids were killed
within 36 h after exposure to 1000 l/l
phosphine for 6 h, with 100% kill attained after exposure to 5000-8000 l/l
phosphine for 6 h. Elevated CO2 levels did not improve the efficacy
of phosphine on LBAM larvae. The optimal treatment was 2000-2500 l/l
phosphine for 4 or 6 h, which killed 96 or 100% of the larvae, respectively.
Under atmospheric CO2 levels, 4000 l/l
phosphine killed 74% of LBAM larvae after 4 h, and 94% after 6 h exposure.