Don’t forget the phosphite!

(Sponsored) Chemically similar but miles apart – in terms of plant nutrition, phosphite plays a very different role to the more familiar phosphate. Dean Konieczka, consultant agronomist with OMEX® Agrifluids USA, explains why phosphite should be in every squash and pumpkin grower’s armory this fall.

Just one less oxygen atom makes all the difference: despite containing the all-important plant nutrient phosphorus, plants can’t access phosphorus in the phosphite form.

Nevertheless, it has another role to play. Some growers may already be aware of phosphite’s role in a disease suppression program, where it can be of great value against diseases such as mildews. Numerous trials have shown how it can complement conventional fungicide treatments, allowing growers to reduce fungicide rates and reduce reliance on particular actives — especially valuable as the legislation around crop protection products continues to tighten.

Incorporating phosphite into an agronomic program can deliver a reduction in residues in food crops, less fungicide resistance pressure, integration with IPM protocols and enhanced plant nutrition.

Of course, it’s important to note that phosphites exhibit ‘disease suppression’, rather than control. Phosphites won’t act against ‘true’ fungal diseases, such as Septoria in wheat. What’s more, scientists have still to agree on the exact mode of action that gifts phosphite this useful property. The most common theory is that it switches on important plant defense genes within the plant. Further research continues.

Phosphite also differs from phosphate in that it’s more soluble. Phosphites display a strong ability to move throughout the plant’s vascular system, moving other nutrients with it. Not only does this make foliar and root uptake more efficient, but it also helps the grower by improving application management.

OMEX® has created several phosphite formulations to suit particular applications and usages; while some, such as PhorcepHite, enjoy full registration as a systemic fungicide, others are primarily for use as a nutritional supplement.

SuperpHite®, for example, is a unique phosphite formulation containing orthophosphate. Because regular phosphites are not plant available, they cannot sustain or provide phosphates to crops until they are converted into orthophosphate — an extremely slow process.

In fall pumpkin and squash production, SuperpHite® can help mitigate the effects associated with disease development brought on by damper, less sunny conditions, while also providing sustained nutrition to the developing fruit. It’s a balance that seems to deliver high quality fruit possessing substantial shelf and storage life.

Application rates for SuperpHite® are between 2-8 pints/acre, whether through foliar application or irrigation.

The OMEX® team is always available to answer queries and questions from growers about vegetable nutrition.

Learn more at www.OMEXusa.com.

The product names and brands referenced here are registered and trademarks of OMEX® Agrifluids, Inc.

© OMEX® Agrifluids, Inc. 2021.