Do diaphragm pumps of hydraulic sprayers affect the viability and infectivity of entomopathogenic fungi?

Abstract: Entomopathogenic fungi (EPF) hold a great potential as biocontrol agents against
some pest. For its application, the technology is used as the one used to apply chemical
pesticides, without taking into account the possible damages the different parts of the sprayer
could cause to the conidia present in the mixture. One of the most common pumps used in
sprayers is the diaphragm or membrane pump. The aim of this work was to study the effect of
diaphragm pumps on the viability and the infectivity of the entomopathogenic fungus
Beauveria bassiana.
For this, the effect of passing a mixture of water with Botanigard 22WP at 125 g/hl, 0
(negative control), 1, 10 and 30 times through the pump on % germination of conidia, %
mortality and % mycosis of Ceratitis capitata individuals, and mixture temperature was
studied.
The results revealed that significant differences were found in conidial germination
percentage and temperature after the 10th pass and onwards. We did not find significant
differences nor in mortality percentage neither in mycosis percentage. In conclusion diaphragm pumps produce mechanical damages on EPF, which do not affect their infectivity, but the increment of temperature could affect their performance as a pest control agent if it reaches values higher than the optimum maximum.