The seed treatment products developed by PGG Wrightson Seeds contain additives that are unique to a particular seed type or end use. These additives all combine to provide a better environment for seedling establishment and early plant growth. Most products combine a systemic insecticide with at least one contact fungicide for highly effective insect and disease protection during plant establishment, along with other beneficial additives. Below is a summary of the additives and the benefits they provide.

Systemic insecticide

Systemic insecticides protect seedlings during the first six weeks of plant establishment when they are most vulnerable to insect pressure. If soil conditions are favourable, chemical active ingredient is released into the soil soon after planting, forming a protective halo around the seed, before it is taken up by the young root system and transported throughout the developing plant via the sap.

System insecticides protect seedlings against root feeding and foliar feeding insect pests.
Systemic insecticides are target specific in terms of the insects they control, providing both knockdown and anti-feeding effects. Insect protection from seed treatment also reduces the risk of disease being introduced through virus vectors such as aphids.

Contact fungicide

Contact fungicides protect seedlings in the first three to four weeks of plant establishment, protecting the root zone from common soil-borne diseases. Young seedlings are most susceptible to disease infection during plant establishment, particularly those under stress.

The importance of fungicide protection is often undervalued, with plant damage in many situations incorrectly identified as some other factor such as nutrient deficiency or insect attack. Fungicides also play a role in deterring birds from eating seed after planting.


Applying lime to legume seed treatment products was developed as a means of providing a localised increase in soil pH around the seedling and supplying calcium in the vicinity of the developing root zone which benefits nodulation. Lime also serves as a benefit in over-sowing situations, with the added weight improving ballistics when seed is applied aerially.



Molybdenum is an essential trace element for plant growth and also nitrogen-fixation by legumes. Uneven distribution of molybdenum in fertiliser has been a problem, leading to uneven distribution in the soil.

The inclusion of molybdenum in a seed treatment ensures the placement of this important trace element is in close proximity to the establishing seedling. 


The clover and lucerne seed coatings contain rhizobia strains specific to those seed types.


Polymers bind active-ingredients and other additives to the seed, ensuring precise coverage and minimising dust emissions which protects applicators, end-users and the environment.


The application of colour in the seed treatment process identifies treated seed from untreated seed. Colour also plays a role in deterring birds from eating seed after planting.