Caligula

Caligula is a liquid fungicide containing a mixture of carboxamide and triazolinthione systemic fungicides delivering preventative and curative activity against early blight in potatoes and a range of foliar diseases in sugar beet.

Product Profile

 Important Information   

Restrictions

Potato and sugar beet: A period of at least 365 days must be observed following treatment with ‘Caligula’ and prior to planting succeeding crops in the MRL group ‘Stem vegetables’. This includes, celery, cardoons, Florence fennel and leeks.

Potato: A minimum interval of 10 days must be observed between applications. No more than two consecutive applications.

Sugar beet: Sugar beet tops treated with Caligula must be disposed of and not fed to livestock

Potatoes

The damage Alternaria inflicts on potato crops varies according to the season – measured losses in unprotected crops range enormously from 5 to 40% – depending on the extent of canopy defoliation. It is generally accepted, however, that the threat posed by the disease in becoming greater, not smaller.

There are several reasons for this escalation in pressure, such as the greater occurrence of favourable conditions during the early season and withdrawal of products that previously delivered effective protection.

Historically, growers were able to rely on products applied for late blight (Phytopthora infestans) to provide sufficient control of early blight, but this is no longer the case. This is in part due to the loss of co-formulated products such as those containing fenamidone, but the introduction of varieties with poor Alternaria resistance is a contributing factor.

A changing climate, especially the greater prevalence of mild and humid conditions in the late spring, has created favourable conditions for disease sporulation.

As the environmental conditions evolve to favour Alternaria spread, it has driven awareness of the damage it can inflict on crops and with it the need to ensure crops are properly protected. This is demonstrated by the increasing prevalence of A. solani strains demonstrating resistance to strobilurin fungicides. Conversely, early blight disease monitoring has found no evidence to suggest a shift in sensitivity to DMI triazolinthione fungicides, such as prothioconazole.

In trials, Caligula has delivered better disease control and yield protection than other products typically used against early blight.

 Caligula gave 37% more control over Alternaria than boscalid + pyraclostrobin Source: Bayer; 16 EU trials, 2013-2018

In this series of direct comparison trials, a preventive sequence of Caligula sprays at approx. 14-day intervals delivered 84% control of early blight in the susceptible phase of the crop, whereas a similar sequence with Signum (boscalid + pyraclostrobin) resulted in 47% control.

Crops treated with Caligula yielded 3% more than crops treated with boscalid + pyraclostrobin Source: Bayer; 14 trials, 2013-2018

The Caligula strategy resulted in 10% mean yield benefit over the untreated, whereas the use of boscalid + pyraclostrobin strategy delivered only a 7% benefit in mean yield.

Similar performance was seen in trials with azoxystrobin. In this series of direct comparison trials, a preventive sequence of Caligula sprays at approx. 14-day intervals delivered 84% control of early blight in the susceptible phase of the crop, whereas a similar sequence with azoxystrobin resulted in 68% control.

Caligula gave 16% more control over Alternaria than azoxystrobin Source: Bayer; 10 EU trials 2013-2016

The Caligula strategy resulted in 6% mean yield benefit over the untreated, whereas the azoxystrobin strategy resulted in 3% mean yield benefit.  

Caligula gave a 3% yield benefit over azoxystrobin Source: Bayer; 2 trials, 2016

The superior control and yield protection benefits of Caligula was also seen in trials involving difenoconazole. Following the same protocol as in earlier trials, Caligula delivered 86% control of early blight is the susceptible phase of the crop, whereas a similar sequence with difenoconazole resulted in 80% of control.

Caligula gave 6% better control over Alternaria than difenoconazole Source: Bayer; 8 trials, 2015-2018

The Caligula strategy resulted in an 8% mean yield gain over the untreated, whereas the difenoconazole strategy gave a 5% yield gain.

Caligula delivered a 3% yield benefit over crops treated with difenoconazole Source: Bayer; 8 trials, 2015-2018

Incidental control of Sclerotinia

In trials performed to assess Caligula’s performance against early blight it was also found to deliver incidental control of Sclerotinia.

A preventative sequence of Caligula delivered a reduction in the incidence of Sclerotinia stem infection of 30%, whereas a sequence of fluazinam achieved a reduction of only 11%.

Caligula made an incidental contribution to Sclerotinia control Source: Bayer; 4 trials, 2013-2015

The Caligula sequence also resulted in a significantly lower incidence of Sclerotia within stems (94% control recorded in one trial), compared with a 40% reduction for fluazinam.

Caligula made a significant contribution towards Sclerotia reduction Source: Bayer; 4 trials, 2013-2015

Sugar beet

Caligula delivered a yield increase over the untreated control of 9.7 t/ha from a single application.  This is inline with that delivered by the previous industry standard of cyproconazole + trifloxystrobin.

A single application of Caligula delivered a yield increase over the untreated of 9.7 t/ha and close to that of the previous industry standard

Source: Bayer; 7 trials, 2019-2020 campaign

Caligula is a co-formulation of fluopyram, an SDHI pyridinyl-ethyl-benzamides, and prothioconazole, a DMI triazolinthione, these active substances belong to different mode of action groups which is essential in promoting resistance management. The inclusion of fluopyram brings more effective action to control. Its higher structural flexibility compared with other SDHIs used for Alternaria control, ensures a better fit around the target site within the disease mitochondria.

Together, fluopyram and prothioconazole combine to protect leaves and stems through a combination of preventative and curative activity that is both contact and systemic. 

Diseases controlled

When used as part of a programme of correctly timed sprays, Caligula gives control of early blight caused by Alternaria species in potato crops and powdery mildew, rust, Cercospora leaf spot and Ramularia leaf spot in sugar beet crops.

Application

Caligula should be applied as a medium spray in 200-300 litres of water.

Caligula should be applied at the first signs of disease. Where diseases pressure remains high a repeat application should be made 10 days later and no more than two consecutive applications of Caligula may be made (in potato crops only). No more than 187 g/ha of fluopyram via foliar treatment to be applied per calendar year.

Apply Caligula on to dry foliage. Do not apply if rain or irrigation is imminent. Caligula is rainfast in the times it takes to dry.

Apply Caligula in 200-300 L/ha of water. The higher spray volumes are recommended where the crop is dense, or disease pressure is high to ensure good penetration to the lower leaves and stem bases. Disease control may be compromised by reducing water volumes, where good spray coverage is difficult to achieve.

Caligula should be applied at 0.5 L/ha with a maximum total dose 1.5 L/ha.

Varieties

Caligula may be used on all commercial varieties of potatoes and crops grown for seed.

Specific requirements for sugar beet

For the safety of those involved, manual removal of bolters should be completed before crops are sprayed. If Caligula has been applied within the last 48 hours, do not enter crops to remove bolters.  Workers handling treated crops or manually removing weed beet or bolted plants with 6 weeks of treatment must wear protective gloves that meet or exceed standard EN374-1:2016 Type A and EN388:2016 (3 1 2 1 X).