ZENECA AGROCHEMICALS ANNOUNCES INVESTMENT IN MESOTRIONE CORN HERBICIDE

The active ingredient has been submitted for EPA review under the 'Reduced Risk' scheme due to its favourable environmental profile. Mesotrione is a triketone compound based on novel chemistry, and is chemically related to naturally occurring plant defence chemicals (allelopathic^* inhibitors).

Mesotrione acts systemically within the plant and on a wide spectrum of broad-leaf weeds affecting corn. The compound acts through inhibition of the enzyme HPPD (4-hydroxyphenylpyruvate dioxygenase), resulting in a number of secondary effects on plant photosynthesis, membrane structure and pigment formation. Within the corn plant, mesotrione is taken up slowly and rapidly metabolised, giving natural selectivity without need for a safener.

Zeneca Agrochemicals' R & D Director, Dr David Evans said, "Mesotrione is a valuable addition to Zeneca's comprehensive corn product range. It is proven to be effective for longer in both pre- and post-emergence weed control, and safe to all major corn hybrids. The product offers superior efficacy against broad-leaf weeds compared with current market leaders, and in addition is safer to the environment."

Construction of the Cold Creek production facility will begin in 2000, with product launch planned for the 2002 season. Mesotrione will be sold in major corn-growing territories including the US and Western Europe, and will complement Zeneca's existing portfolio of crop protection products for use on corn.^**

Note to News Editors:
	Zeneca Agrochemicals is the crop protection and plant science business of AstraZeneca. It is the third largest supplier to this international market, with sales in 1998 of $2.88 bn in over 130 countries. AstraZeneca (Registered Office, London) is a leading international pharmaceuticals and bioscience group with 1998 pro forma sales of $17.26 bn.

*Allelopathy - adverse influence exerted by one plant over another, or by one strain over another within a species, through the production of a chemical inhibitor. E.g. Bottlebrush family (Callistemon).

**Zeneca Agrochemicals' range of crop protection products for use on corn includes, 'surpass', 'Force', 'Warrior', 'FulTime', 'Touchdown' and 'Gramoxone'. (US)

**Zeneca Agrochemicals' range of crop protection products for use on corn includes, 'Trophée', 'Mikado', 'Milagro', 'Karate', 'Touchdown' and 'Gramoxone'. (EUROPE)