Bitter Pit

Bitterpit Overview

Bitter pit is a plant physiological disorder that results in localized lesions on the surface of fruit. It is the result of cell breakdown and oxidation caused by inadequate calcium and cell wall strength.

Key Facts

Calcium and Silicon

Improved calcium uptake in the plant for increased calcium concentration in the fruit must occur during early cell development. This cell development timing starts at the latter stages of bloom and ninety percent of cell calcium uptake occurs during a three-week window of time. A highly beneficial element that facilitates the cell organization and rigidity is silicon. Silicon is taken up in the plant as mono-silicic acid. Application of the combination of plant available calcium and plant available silicon has proven to be very beneficial for reducing bitter pit. Increased uptake of calcium and silicon also strongly influence the ability of the plant to withstand abiotic stress.

Illustration showing effects of no calcium or silicon.

Illustration showing effects of calcium.

Illustration showing effects of added calcium and silicon.

Redox Calcium Technology

Two unique calcium products offered by Redox are:

• Mainstay Calcium – A reacted nutrient product high in calcium (20%) with Redox microencapsulation technology for high uptake and movement within the plant.

• Mainstay Si – A reacted nutrient product high in calcium (10%) and silicon (22%) with Redox microencapsulation technology for high uptake and movement within the plant.

Illustration of plant without Mainstay Si

Illustration of plant with Mainstay Si

Bitter Pit Priorities
Excellent horticultural management: Crop Load, Tree VigorManage Soil Health: Soil Moisture, Root Growth and DevelopmentNutrition Management: Nitrogen, Calcium, Potassium
Redox Solution

Mainstay Si

Apply 0.5 gals/acre at petal fall through a foliar application.

Apply 0.5 gals/acre at 14 days post petal fall through a foliar application.

Mainstay Calcium

Apply 3-5 gals/acre at early bloom with a soil application

Apply 3-5 gals/acre at late bloom/petal fall with a soil application

Apply 3-5 gals/acre 14 days post petal fall with a soil application

Note: use higher rates for problem orchards.

Redox Results