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Notes

The levels (1—5) represent the populations of insects observed on the plants.

1 Scales present on the plants: 1 = 1—25 scales.

2 Mealy bugs on the plants: 1 = 1-25, 2 = 26-50, 3 = 51-75, 4 = 76-100, 5 = >100 insects.

4 Thrips on the flowers: 1 = 1-10, 2 = 11-20, 3 = 21-30. Fo = Frankliniella occidentalis, Tt = Thrips tabaci, Hh = Heliothrips haemorrhoidalis.

Notes

The levels (1—5) represent the populations of insects observed on the plants.

1 Scales present on the plants: 1 = 1—25 scales.

2 Mealy bugs on the plants: 1 = 1-25, 2 = 26-50, 3 = 51-75, 4 = 76-100, 5 = >100 insects.

4 Thrips on the flowers: 1 = 1-10, 2 = 11-20, 3 = 21-30. Fo = Frankliniella occidentalis, Tt = Thrips tabaci, Hh = Heliothrips haemorrhoidalis.

the stems. The species of aphids varied but were usually Aphis gossypii Glover, Aphis fabae Scopoli or Myzus persicae Sulzer. On some aloes a proportion of the aphids were parasitised by species of Aphidius. These parasitoids were released to control aphids on other plants growing in different zones of the glasshouses and breeding populations have become established. No parasitoids were released specifically to control the aphids on aloes. Ants were seen farming the aphids and mealy-bugs on a few plants. It was observed that the number of mummified aphids (i.e. parasitised aphids) was lower on the ant-infested plants than on the plants with no ants. This could be because the ants were deterring the beneficial insects from attacking the pests on the aloes (Beyleveld, 1973).

The following species of Aloe supported aphids: A. excelsa, A. marlothii, A. mutabilis, A. pienaarii, A. pluridens , A. tomentosas, A. vaombe and A. wollastonii (Table 17.1).

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Aloe and Your Health

Aloe and Your Health

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