تحديد فعالية بعض العزلات المحلية للنيماتودا الممرضة للحشرات ضد حافرة أوراق البندورة الطماطم Tuta absoluta (Meyrick)‎ في الحقل و تحت ظروف المختبر

الملخص EN

The efficacy of the infective juveniles (ijs) of two different local isolates (vh11, dkh) of the entomopathogenic nematode (epn) heterorhabditis bacteriophora, and a local isolate (rst) of steinernema carpocapsae was investigated against the larvae and pupae of tomato leaf miner tuta absoluta (meyrick) (lepidoptera: gelechiidae) under laboratory and field conditions during the 2018 growing season.

these isolates were obtained from the biological control research and studies center, faculty of agriculture, damascus university, Syria.

larvae of t.

absoluta were collected from an infested tomato field in the village of karhasar in amouda subdistrict, al-Hasaka governorate, syria, and mass produced on tomato plants in a climate-controlled room.

the tomato leaf miners were exposed to each nematode species at the rate of 50 ijs/cm2 on tomato plants in cages.

t.

absoluta was susceptible to all epns tested but with different degrees of susceptibility of the larvae to epns infection, based on the isolate used.

the most effective isolate on t.

absoluta larvae was isolate dkh, leading to 80.75% mortality, whereas the least effective was isolate rst, leading to 68.88% mortality.

under laboratory conditions, the epns were applied at different inoculation rates (1, 2, 5, 10, 15, 20, 25 and 40 ijs per larva) to the 4th instar larvae of t.

absoluta.

the mortality rates produced by the isolates rst, dkh and vh11 were in the range 21.8-90, 16.11-67.23 and 13.6-86.25%, respectively.

the ld50 values for the three isolates rst, dkh and vh11 were 7.8, 18 and 16 ijs per larva, respectively.

based on the results obtained, the isolate rst was the most efficient nematode species, and can be applied against the larvae of t.

absoluta inside the mines and against pupae.

however, the isolate rst caused a low mortality rate of larvae inside the mines (15%) and the pupae (5.5%).