Table 1. Density, survival and fecundity of hemlock woolly adelgid and dry mass of new hemlock leaders in July on unfertilized hemlocks and on ones that had been fertilized with nitrogen 6 months before or at the time of infestation1 on 19 April
Treatmentnumber of adelgids per 20mm2% adelgid survivalnumber of eggs per adultbiomass (mg) of new hemlock growth
Fertilized
before infestation13.7 ± 4.1a72.5 ± 17.6a186.7 ± 28.7a  69.7 ± 9.5a
at infestation14.1 ± 3.9a79.7 ± 16.7a198.2 ± 29.3a66.1 ± 10.8a
Unfertilized  2.7 ± 1.1b  31.3 ± 8.6b88.6 ± 14.3b85.8 ± 11.3b

  • ↵1 Means (±SD) in each column followed by different letters differ significantly (p = 0.001) by ANOVA.