Turf Fungicide Fundamentals 15
intercellular spaces and cells that do not contain living protoplasts (apoplastic transport) (Fig. 1.4). Only phosphonic acids move symplastically, while all other penetrants move in an apoplastic fashion (Table 1.3). Fungicides capable of apoplastic transport are further divided into those that are xylem mobile (acropetal penetrants) and those with limited migration across leaf tissues (local penetrants). In most cases, fungicides within a given class share a common phytomobility, such as local penetrant dicarboximides and xylem mobile DMIs. The notable exception is the QoI fungicide class, which includes both acropetal and local penetrants. The disease control advantage provided by penetrant fungicides lies in their ability to restrict the growth of pathogenic fungi inside the plant; i.e., they are chemotherapeutic. As long as fungitoxic concentrations persist in
Table 1.3. Phytomobility of active ingredients in turf fungicides Fungicide
Phytomobility classification
Movement throughout the plant
… … … … … …
Movement among cells
chlorothalonil mancozeb thiram PCNB chloroneb etridiazole
Contact Contact Contact Contact Contact Contact
… … … … … …
iprodione vinclozolin trifloxystrobin pyraclostrobin cyazofamid fludioxonil polyoxin D
Local penetrant Local penetrant Local penetrant Local penetrant Local penetrant Local penetrant Local penetrant
Translaminar Translaminar Translaminar Translaminar Translaminar Translaminar Translaminar
Uncertain Uncertain Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic
azoxystrobin fluoxastrobin fenarimol metconazole myclobutanil propiconazole tebuconazole triadimefon triticonazole flutolanil boscalid mefenoxam thiophanate-methyl propamocarb fluopicolide
Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant Acropetal penetrant
Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile Xylem mobile
Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic Apoplastic
fosetyl aluminum phosphonic acids
Systemic penetrant Systemic penetrant
Ambimobile Ambimobile
Symplastic Symplastic