Welcome to the April edition of the Life Scientific Newsletter.
As we continue to bring more reverse-engineered products to market, we are constantly looking for new information about well-established active ingredients and products to help our customers make informed decisions. Whilst R and D manufacturers concentrate on new chemistry, there are still things to learn about older active ingredients and how they fit in current programmes. Examples of this can be seen in this edition of the newsletter where we have new data on the persistence of BOSCLER (our 500g/kg WG formulation of boscalid) in oilseed rape and the activity of spiroxamine, in our new product FLEXURE, on today’s natural mildew strains.
FLEXURE – new product and new information
A new product for us this year is FLEXURE which has approval for use in wheat, barley, oats, rye, durum wheat and triticale.
FLEXURE contains prothioconazole, a reliable DMI fungicide, and spiroxamine, an amine (“morpholines”), the combination having useful activity on powdery mildew, rusts, Rhynchosporium and net blotch.
Continuing our development work, Life Scientific undertook a trial this year with ADAS to investigate the activity of FLEXURE on wheat powdery mildew. The trial was conducted in the glasshouse comparing FLEXURE at full rate (1.25L/Ha) and half rate, with standards including fenpropidin, cyflufenamid, prothioconazole (AURELIA) and sulphur.
The products were tested for their protectant and curative properties.
Protectant treatments were applied 5 days before the plants were inoculated with powdery mildew and curative treatments applied 5 days after inoculation.
Weed control in maize
It is time to think about maize drilling and weed control programmes.
Competition from weeds is most damaging to maize in the early stages, so it is important to use an early effective herbicide programme.
Our maize herbicide, BASILICO, which contains mestrione was successfully re-registered in 2023 for use in forage and grain maize with a new MAPP number – 19927.
When applied at its approved rate of 0.75L/Ha BASILICO will control the following important maize weeds.
Mesotrione is a very active herbicide, killing weeds mainly by contact activity, so good coverage of the target is important. The product should be applied when the weeds have emerged.
The crop must have reached two leaves, and the latest timing is before the maize exceeds the eight leaf stage. BASILICO is physically compatible with other named maize herbicides and can be a key part of any weed control programme in the crop.
Sclerotinia control in oilseed rape – more new trial results
Sclerotinia stem rot is an important disease of oilseed rape in the UK and is the reason given for almost 30% of total fungicides used in the crop according to Fera’s 2022 Pesticide usage survey report of arable crops in the UK. Given the right conditions, Sclerotinia can be very damaging by stopping movement of water and nutrition through the plant’s vascular system. In extreme circumstances oilseed rape yields can be reduced by 50% and total plant loss is also possible.
Sclerotinia sclerotiorum infects crops in the spring when the fungal ascospores are produced, with the highest risk being during warm humid weather when the crop is in flower, as the spores use petals and pollen as a food source in order to develop.
Effective control of the disease relies largely on protectant fungicides, such as BOSCLER, an SDHI fungicide containing 500g/kg boscalid, formulated as a WG. Knowing how persistent the products are after application is useful as protection needs to cover the whole period when the crop is most at risk. In some years, more than one spray may be needed
As with any fungicide application, it is good practice to follow resistance management guidelines and it makes sense to mix boscalid with a fungicide with a different mode of action to help prevent resistance developing. AURELIA (an EC formulation containing 250g/L prothioconazole) has approval for control of Sclerotinia stem rot when applied at early to full flowering but, if light leaf spot is present at this timing, it is advisable to mix boscalid with a non-azole based fungicide such as AZOXYSTAR (containing 250g/L azoxystrobin) to avoid the development of resistance in this disease.
Life Scientific commissioned ADAS Boxworth to undertake a study investigating the persistence of boscalid mixtures with prothioconazole against Sclerotinia. The trial included Life Scientific’s products, BOSCLER (boscalid 500g/kg WG) and AURELIA (prothioconazole 250g/L EC).
A crop of oilseed rape was sprayed in the field on 13th April at GS59 with rates of boscalid 500g/kg WG ranging from full rate (0.5kg/Ha) to a 30% dose, and the rates of prothioconazole 250g/L EC ranging from full rate (0.7L/Ha) to a 40% dose.Leaves were sampled up to 21 days after application, placed in sealed humid containers, and inoculated with a petal that had been dipped in a suspension of sclerotinia ascospores. The leaves were then assessed 8 days after inoculation and any Sclerotinia lesions were measured. From this, the percentage disease inhibition for the 21day period after spraying was calculated for the different dose rates.
All the treatments reduced lesion size and development, and showed good persistence for the 21day period after the crop was sprayed but, as sclerotinia control relies on protectant treatments, it is important to use the appropriate dose to cover the periods at risk from the disease. The most effective and persistent treatments in this trial, giving good control for up to 21 days, were those where boscalid had been applied at the full 0.5kg/Ha rate. Rates below 0.5kg/Ha in the mixtures gave lower levels of efficacy and greater decline in activity over the 21day trial period.
Field conditions were dry when the trial crop was sprayed and stayed dry for the sampling period. In warm wet conditions, ideal for the development of Sclerotinia, it is likely that the sprays would be less persistent so it is even more important to keep the dose rates high to have the best chance of covering the infection period and protecting crops against disease.
