AGROCHEMICALS germination and significantly inhibited lesion development and sporulation of fungal pathogen . TTO was found to disrupt the fungal cell membrane and cell wall in plant tissue infected with pathogenic fungi , which explains why it exhibited strong curative activity against fungal pathogens , enabling growers to use it even when the disease is already visible on the tissue . In addition , TTO was found to be an activator of the plant ’ s defence mechanisms and systemically induced resistance in plants . Sterol biosynthesis inhibitors , including difenoconazole , affect the fungal cell membrane by inhibiting
C 14 demethylation of lanosterol or 24-methylenedihydrolanosterol . This is a biosynthesis step that occurs during the conversion of lanosterol to ergosterol , the final product of fungal cell membrane sterol synthesis . The different modes of action of TTO and difenoconazole - a combination of a natural product with broad-spectrum activity and a traditional site-specific chemical - makes Regev an effective and unique tool for resistance management which is suitable for integrated pest management programmes . This combination results in a reduced synthetic chemical load on the environment compared to other mixtures based on two traditional chemicals .
Field trials
Regev is currently used for controlling a broad range of diseases on arable crops , cereals , fruits crops and vegetables . Diseases it effectively controls include powdery mildews , apple scab ( Venturia inaequalis ), black Sigatoka ( Mycosphaerella fijiensis ) in banana , species of Alternaria , Cercospora , Botrytis , Rhizoctonia , Pyricularia , Helminthosporium , Sclerotium and more . Numerous trials have been conducted with various crops in different countries . Here we present an example of Regev ’ s activity against black Sigatoka in bananas in a field trial in Colombia , The efficacy of Regev applied alone was compared to that of systemic fungicides , each being applied in tank mixture with a protectant fungicide mancozeb . Untreated banana plants served as controls . Four foliar sprays of each fungicide or mixture were applied at spray volume of 19 L / ha at ten-day intervals . The results ( Figure 1 ) show that systemic fungicides tank-mixed with mancozeb reduced disease severity , as expressed by percentage of infected leaf area compared to untreated control plants . However , Regev was significantly more effective in controlling black Sigatoka . Regev has a unique , multi-functional activity . It presents a lower probability for resistance development or crossresistance in plant pathogens , so it could be an important tool in preventing development of cross-resistance during the season . Its application can be rotated with products that exhibit differing modes of action and to which populations of fungal pathogens have shown a loss of sensitivity , so that population of pathogens less sensitive to chemical products can be reduced . Regev is already registered in Israel , Philippines , Serbia , the US and various Latin American countries for various crops and diseases . It is currently in the process of registration in Brazil , Mexico and the EU .
Summary
The different modes of action of TTO and difenoconazole make Regev an effective and unique tool for resistance management . It presents multiple modes of action ( FRAC Groups BM 01 and G1 ) to help prevent the development of resistance . This combination results in a reduced chemical load on the environment compared to other mixtures based on two traditional chemicals , leading to reduced residues in food . The preventive and curative activity of Regev , related to its efficiency of contact , mesosystemic plus systemic activity by a single application , together with the indirect activity via the host plant by systemic resistance , leaving little residue and providing significant added value to growers , make Regev an important component in plant disease control . Regev has an expanded spectrum over either component alone and has demonstrated activity on a wide range of plant diseases . It can therefore be an effective and easyto-use bridge solution for controlling various diseases . •
* - Regev is a registered trademark of STK Bio-Ag Technologies
J j
Professor Moshe Euveni
CHIEF SCIENTIST
STK , STOCKTON GROUP moshe @ stk-ag . com www . stk-ag . com
29