Population densities of the serpentine leaf miner Liriomyza trifolii (Burgess)‎ (Diptera : Agromyzidae)‎ and the associated parasitoids Diglyphus isaea and Opius pallipes on two weed host plants

الملخص EN

The present study was carried out in Alzawia region.

Blackberry nightshade (Solanum nigrum) and Sour clover (Melilotus indicus) were selected as a summer and winter host plants during the growing seasons 2020 and 2021.

L.

trifolii larvae showed three peaks of abundance on nightshade and sour clover recording (11, 19 and, 29) and (58, 119 and, 38 individuals/ 100 infested leaflets) respectively.

On the other hand, D.

isaea recorded three peaks of abundance on sour clover and nightshade with (27, 55 and, 66) and (9, 11 and, 19 individuals/ 100 infested leaflets) respectively.

The percentage of parasitism ranged between (12.9% - 91.3%) on sour clover and (0.0% - 59.7%) on nightshade.

The larva pupal endoparasitoid O.pallipes recorded three peaks of abundance on sour clover and nightshade with (15, 25 and, 14) and (8, 10 and, 12 individuals/ 100 infested leaflets).

The percentage of parasitism ranged between (0.0% - 46.8%) on sour clover and (0.0% - 72.7%) on nightshade.

Correlation coefficient (r) between D.isaea and L.

trifolii recorded (0.91 and 0.75) on Nightshade and Sour clover.

On the other hand, r value recorded (0.52 and 0.39) for O.

pallipes on Nightshade and Sour clover respectively.

It could be concluded that, L.

trifolii, D.isaea and O.

pallipes recorded the highest average population occurrence on sour clover.

On the other hand, The percentage of parasitism of D.isaea and Infested leaflets recorded the highest occurrence on sour clover.

While The percentage of parasitism of O.

pallipes was the highest on nightshade.

It could be seen that, weed host plants can play a vital role in keeping the populations of L.

trifolii and its parasitic fauna in the absence of their economic favorite host plants.