Rt. Sterner et Ca. Ramey, DETERIORATION OF LECITHIN-ADHERED ZINC PHOSPHIDE BAITS IN ALFALFA, International biodeterioration & biodegradation, 36(1-2), 1995, pp. 65-71
A 2 . 00 (+/-0 . 36)% zinc phosphide (Zn3P2, CAS no. 1314-84-7) steam-
rolled-oat (SRO) greats bait containing 1 . 04% lecithin vehicle was b
roadcast in alfalfa (Medicago sativa). Samples of bait were collected
immediately after broadcast, and 1, 7 and 14 days after exposure to ex
istent agronomic and climatological conditions. Analyses of respective
samples yielded 1 . 80 (+/-0 . 36)%, 1 . 18 (+/-0 . 04)%, 1 . 20 (+/-
0 . Il)%, and less than or equal to 0 . 26 (+/-0 . 05)% Zn3P2. A simil
ar to 10% loss of Zn3P2 occurred immediately due to mechanical broadca
st; similar to 33% loss was noted 1-7 days after exposure to pH 6 . 0
soil and 0 . 05 cm rainfall; and greater than or equal to 87% loss of
Zn3P2 occurred by day 14 following an additional 0 . 96 cm rainfall. M
echanical, precipitation and soil-acidity factors are viewed to reduce
the concentration of Zn3P2-grain baits in crop situations. Lecithin-a
dhered Zn3P2 baits showed a relatively rapid decline in concentration
of active ingredient (A.I.) after broadcast and exposure to slight moi
sture - a useful attribute of these baits in areas where hazards to no
ntarget wildlife are of concern.