Intensity of honeydew excretion by Cinara pectinatae (Noerdl) aphis
1993
Galuszka, H. (Krakow Agricultural University, (Poland). Dept. of Bee)
Observations on the frequency of excretion of honeydew drops by Cinaria pectinatae in a 10-day cycle were carried out in July, August and September. Under 20 aphids feeding on fir twigs used photographic plates were placed for 2 h between 2 and 4 p.m. The maximum honeydew excretion occurred in mid-August, the mean number of excreted drops varying from 6.7-7.4 (aphis) 2 h. At that time the gradation of populations took place. Aphids of small and medium size prevailed, however, differences between the size groups were statistically non-significant. A decrease in the intensity of honeydew excretion slightly preceded the peak emergence of the population. If the gradation of aphis populations occurring in July and mid-August and favourable weather conditions are maintained, a rich harvest of honeydew for bees be expected
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