You may use small same-size, same-age peripheral discs of an agar culture colony of the fungus. However, as the main inoculum of the fungus are its conidia, You had better to inoculate tomatoes with a given volume of a conidial suspension of a given spore number per ml. You can spray the suspension. If You are willing to do localized inoculations similar to the method You have followed before, I suggest to put few microliters (of total given volume) of the above-mentioned suspension. You may use paper discs contaminated with such aliquots but this is not a rational approach (change of inoculum potential).

For discs, You may distribute very diluted conidial suspension on water agar plate, and after the appearance of fleck like tiny colonies You can use sterilized cut sampler-tips and toothpick to take small discs with single fleck colony and use them for inoculation.

thanks for the advice and ideas.

I will certainly keep you informed of the progress of these trial.

We inoculated tomatoes plants, detached leaves , and fruits by Botrytis cinerea by two ways: mycelial plugs or conidial suspenions. 1) Detached leaves: Tomato detached leaves were taken from 7 and 5-week - old plants. Detached leaves were placed in plastic containers (30 × 45×15 cm) with a grid on the bottom. A wet filter paper was placed beneath the grid to maintain high humidity. Leaves were placed upside down on the plastic grid in the bottom of the plastic containers. Detached Tomato leaves were

inoculated with 5-mm - diameter mycelial agar discs of B. cinerea taken from 6-day - old cultures on PDA with the disc placed in the middle of three leaves of tomato plan. Conidial inoculums collected from sporulating cultures of B. cinerea obtained after growing the fungus on 50-mm diameter PDA plates and incubated in the light at 20 °C. Cultures (12 - 16 day - old) were flooded with deionized sterilized water, and the conidia were scraped from the surface and transferred to 500 ml flask. The spore suspension was then filtered through 2-3 thin layers of cheese cloth. A number of spores in the suspension was adjusted to give a spore

concentration of 100000 spore /ml by using a haemacytometer. Phosphate

(KH2PO4) and glucose (D+-glucose-monohydrate) were added to the

suspension as nutrients (1 g/l). Twenty μl of spore suspension were placed on the lower surface of the leaves . The leaves were left at room temperature for 30 minutes to allow the spores to settle down; the boxes were then closed with a plastic transparent cover in order to maintain air humidity above 95 % and incubated at 20 °C with 12 h

photoperiod in the growth room. Disease evaluated by measuring the radius of the gray mould lesion growth.

When used the whole tomato plants, we sprayed by conidial suspension prepared as mention before and coverd the plants with transparent plastic sacks and inoculated for 10-12 day, the disease severity was evalated as %.

can we have the references for disc inoculation

thank you