Jm. Schalk et al., RESPONSE OF CATERPILLAR PESTS AND THE PARASITE DIADEGMA-INSULARE TO COLLARD CULTIVARS AND A PYRETHRIN INSECTICIDE, HortScience, 28(4), 1993, pp. 308-310
There were no differences in mortality, plant preference, or plant dam
age when diamondback moth (DBM) (Plutella xylostella L.) larvae were t
ested in no-choice and free-choice tests using leaf disks of resistant
('Green Glaze') or susceptible ('Vates', standard commercial cultivar
) collards (Brassica oleracea Acephala group). No residuals of the pyr
ethrin insecticide Asana-XL (esfenvalerate) were detected 6 days after
its application when DBM larvae were exposed to excised foliage for 7
2 hours. In a field test, more imported cabbage worm (ICW) (Pieris rap
ae L.) eggs were found on 'Vates' treated with the insecticide than on
nontreated 'Vates' or nontreated or treated 'Green Glaze'. The fewest
ICW, cabbage looper (CL) (Trichoplusia ni Hubner), and DBM larvae wer
e found on the insecticide-treated cultivars. Fewer caterpillars were
found on 'Green Glaze' than 'Vates'. An additive effect of plant resis
tance and insecticide application lowered counts of DBM, ICW, and CL l
arvae. Percent parasitism of DBM by Diadegma insulare Cresson (Hymenop
tera: Ichneumonidae) was lower on cultivars treated with the insectici
de. Field plant damage ratings were higher for nontreated 'Vates' and
lowest for treated cultivars, but nontreated 'Green Glaze' had a signi
ficantly lower feeding damage rating than nontreated 'Vates'. Chemical
name used: (S)-cyano (3-phenoxy phenyl) methyl-(S)-4 chloro-alpha (1-
methylethyl) benzeneacetate [esfenvalerate (Asana-XL)].