Shadecloth was put on the high tunnel on Tuesday, July 18 after white drupelet symptoms appeared on the raspberries that is associated with solar radiation (UV light) – see http://ipm.ucanr.edu/PMG/r71800111.html  UC IPM Caneberries White Drupelet. This shadecloth is 50% shade. We looked at PAR (photosynthetically  active radiation) both inside and outside the tunnel both before and after the shadecloth was installed.

PAR readings taken 7-12-17    1:00 – 1:10pm

Outside tunnel – 2149 micromoles per meter squared per second

Inside tunnel – 1507 micromoles per meter squared per second – 70% compared to outside.

PAR Readings taken 7-19-17    1:20pm

Outside tunnel – 2209 micromoles per meter squared per second

Inside tunnel with shadecloth – 845 micromoles per meter squared per second – 35% compared to outside.