SUSCEPTIBILITY OF SIX FABA BEAN VARIETIES TO CERTAIN HOMOPTEROUS INSECTS INFESTATION AND TRANSMISSION EFFECIENCY OF FABA BEAN NECROTIC YELLOW VIRUS

The present investigation aimed to study the effects of some faba bean varieties (Giza429 ,Line 69,Giza3,Giza461,Giza 4 and Giza22 )   on the population density of   aphids , leafhoppers and whitefly insects  .The  obtained results show pronounced  differences in the population density of the aforementioned   insects under tested varieties. The tested six varieties of faba bean can be arranged descendingly  according to the degree of infestation with insects as follows Giza 22  ;
Giza4; Giza461  ; Giza 3;Line69 and  Giza429 .Chemical analysis results showed a positive relationship between protein , carbohydrate contents and pH values with aphids, leafhoppers and whitefly infestation in all faba bean varieties, while reverse relationship between pH values and insect infestation. Negative relationship between insect infestations and quantity of yield was also recorded.
Therefore, it could be recommended that using suitable plant variety must be included in the integrated pest management programs.
 Transmission experiments of faba bean necrotic yellow virus (FBNYV) by aphid insectsAphis craccivora Koch and Myzus persicae Sulz. confirmed the ability of these aphid species to transmit the FBNYV.
The results of virus transmission could be summarized as follows:
i) The acquisition access feeding periods ranged between 10 hrs and 7 days for A craccivora and 16 hrs to 9 days for M persicae.
ii) Latent  periods in aphid insect vectors  ranged between 4 and 6 days.
iii) Inoculation access feeding periods ranged between 2 hrs and 5hrs.
iv) Latent  period of virus in host plants ranged from 6 to8 days in celery plants and 12 to18 days in faba bean plants. 
v) Retention periods of the virus in the infective aphid vector ranged between 24 - 28 days.