Amaranthus hypochondriacus L. and Amaranthus caudatus L. Special attention was
paid to phytophagous insects, which development was studied both on cultivated and
wild amaranth species.
Results and discussion. With a comprehensive study of the amaranth
entomocomplex we paid attention to insects not only on the amaranth crop during
vegetation, but also insects in the plant residues.
It was proved that plant residues of amaranth attract insects of different trophic
specialization, which in turn forms a special complex entomocoenosis. The most of
insects pass here maturation feeding, and other find refuge for winter diapause [10].
We have found 28 insect species from five orders in plant residues of amaranth. These
species are typical for agrocoenoses, particularly adults of Carabidae (7 species),
Scarabaeidae (2 species), Staphylinidae (1 species), Histeridae (4 species),
Coccinellidae (1 species), Tenebrionidae (1 species), Curculionidae (3 species), larvae
of Diptera (Muscidae – 2 species, Sepsidae – 1 species). Besides these insects, crickets
(Gryllidae), earwigs (
Dermaptera
), adult bugs (Pyrrhocoridae – 1 species, Lygaeidae –
2 species) were found in plant residues of amaranth. The pests of amaranth were absent
in its plant residues.
The insects of amaranth during vegetation were divided on two groups:
inhabitants of herbaceous layer and inhabitants of generative organs.
Among inhabitants of herbaceous layer 187 species of 67 families from 10 orders
were revealed (Table 1).
Insects of herbaceous layer were presented by such trophic groups:
1) polyphagous phytophags;
2) olygophags, with participation of amaranth in the list of their food plants;
3) olygophags, without participation of amaranth in the list of their food plants;
4) predators, mainly attack the phytophags of amaranth;
5) parasitoids, which have maturation feeding by amaranth pollen, some species
parasitize on amaranth pests;
6) saprophags, whose larvae eat dead plant residues.
From the complex of polyphagous sucking phytophags,
black bean aphid
(Aphis
fabae Scopoli, 1763) was the most abundant and harmful, it is one of the main amaranth
pests in the region of our research [27]. It is especially harmful on young plants: it
slows down growth, causes deformation of leaves, and the death of young plants at
high population density of aphids [8]. Entomiphags of
black bean aphid
are represented
by 16 insect species, with the highest meaning of coccinelid beetles (Coccinelidae) and
Aphidiidae [25]. It was noted that the aphids as pests have no economic value in the
natural area of amaranth as well of in southern regions of its cultivation, except for
Kenya, where the green peach aphid (Myzus persicae) damages amaranth.
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