Albus lupin is a re-emerging crop in Western Australia, the current variety, Amira, has improved anthracnose tolerance but can still suffer significant yield loss under high disease pressure. Increasing pressure from sclerotinia exists in environments suitable for production of Amira, particularly on heavier soil types.
Historically sclerotinia infection has been sporadic in lupin and cases of significant crop loss or grain contamination were infrequent. However, with increasing incidence of infection in canola, inoculum pressure (soil borne sclerotia) is increasing and lupins grown in higher rainfall environments where canola is also part of the rotation are exhibiting increasing incidence of infection.
No fungicides are currently registered for management of sclerotinia in lupin, permit applications for new products are in place but very little is known about potential timing of fungicide application and any impact that may occur.
This trial assesses the capacity of fungicide intervention to reduce impact of post flowering diseases, specifically sclerotinia, on grain yield and quality in albus and narrow leafed lupins.
It will also give a better understanding of the infection process of sclerotinia in lupins.
|Site||Geraldton Research Facility, Woorree|
|Crop||Lupins: Albus (var. Amira) and narrow leaf (Mandelup)|
Prosaro* at 450mL/ha applied at different growth stages across both Albus and narrow leafed lupins.
Six treatments x three repetitions
*Note: no foliar fungicides are currently registered for sclerotinia control in lupins, this product is being used for research purposes only.
Incidence and severity of sclerotinia of stem and pod infection
General trial details and observations
Both Amira and Mandelup bulk areas were well grown with good plant density (sown at 140kg/ha and 90kg/ha respectively). At the time of spraying full canopy closure had occurred in both crops. The trial was designed to have plots running across the interface between Amira and Mandelup crops, that is identical trials adjacent in the two crop types.
At T2 different nozzles were utilised (more suitable to due to higher wind speed), this time of application appears to have been less effective, potentially nozzle type or wind conditions may have contributed to this response.
Disease assessments were made on 4 October (post flowering, prior to onset of leaf drop), assessing eight individual plants at five points within each plot for incidence and severity of sclerotinia. At this time significant lodging was occurring in NIL, including 10-20% plants affected by ground level Sclerotinia sclerotiorum lesions. Disease rating scale was 0-5 (0 = no disease, 1 = branch lesion, 2 = stem lesion, 3 = lesion killing branch, 4 = lesion killing stem, 5 = stem base lesion killing plant). Lesions affecting pods or main spike were counted separately for each plant. Additional notes were taken of other diseases occurring and notable plant damage. Anthracnose was evident in only one plot (plot 2) of the Amira trial.
In-crop observation in the trial indicates that often main stem infection was associated with lesions originating in leaf axils or with leaflets wrapping around the stem. The contribution of flower petals to stem infection is not known. Flower spike infection was also very common but the exact mechanism is also poorly understood.
|7 July||100% bud, 25% flower (<50% bloom)||100% flower (50% bloom)||Sprayed T1 plots. No disease symptoms observed|
|15 July||>75% flower (50% bloom)||100% flower (100% bloom)||Sprayed T2 plots. No disease observed|
|20 July||100% flower (100% bloom)||Flower (50% bloom) – 1cm pod||Sprayed T3 plots. No disease observed|
|3 August||50% flower –1cm pod||1-3cm pod||Sprayed T4 plots|
|4/5 October||Grain fill||Grain fill||Assess 40 plants/plot, disease incidence and severity|
|Date||7-Jul (T1)||15-Jul (T2)||20-Jul (T3)||3-Aug (T4)|
|Wind Speed Km/hr||1.8||13.3||1.8||4.3|
|Nozzles||DG TEEJET 110 02 VP nozzles||Low drift - XR 11002||DG TEEJET 110 02 VP nozzles||DG TEEJET 110 02 VP nozzles|
Amira albus lupin trial
Sclerotinia lesions were evident at time of assessment, with majority of infection affecting main spike or pods rather than stems. Limited ground level infection was evident in this trial.
Stem lesion incidence was reduced by 40-50% by fungicide application but individual timing treatments were not significantly different from Untreated (NIL). Both sclerotinia and phomopsis were isolated from stem lesions with the majority of lesions being related to sclerotinia infection.
All fungicide timings reduced main spike sclerotinia infection as well as pod lesions. Incidence of main spike infection was significantly reduced by all applications except T2.
Anthracnose was present in only one plot (seed borne) so comparisons between treatments was not possible.
Yield in T3, T4 and T1+T3 treatments were at least 0.4t/ha greater than the Untreated control (NIL), this difference is significant at p=0.1. Fungicide application does not appear to have been damaging to yield.
No sclerotia were present in harvested seed.
|Treatment||Main stem lesion||Branch lesion||Main stem/branch lesion||Stem base infection||Main spike lesion (sclero)||Pod lesion (phomopsis)||Pod and/or spike|
|T1 + T3||3.3||4.2||5.0||0.8||0.8||9.2||10.0|
|Treatment||Yield (t/ha)||Grain weight (g/1000)||Protein (%)|
|T1 + T3||2.94||371.8||32.2|
Mandelup narrow leafed lupin trial
Sclerotinia was present at time of assessment, with lesions evident at stem bases, on main stem and to a lesser degree on main spike and pods.
Incidence of lodging and premature senescence were estimated on a per plot area basis. Across the site approximately 35% of plants were lodged resulting in approximately 20% premature senescence, no fungicide responses were evident. Some lodging and plant death was related to sclerotinia stem base infection, however a significant proportion was independent of obvious disease symptom, possibly related to high plant density, heavy canopy cover and susceptibility of the variety Mandelup to lodging under these conditions.
Stem base infection was present in 5-10% of plants and there was no apparent effect of fungicide application on incidence. The majority of affected plants were lodging, senescing rapidly and not likely to contribute to yield.
Stem and branch infection, excluding stem base, was reduced by 50-60% by T3 and T4 sprays. Similarly >50% reduction in main spike infection incidence was evident from these sprays.
Yield differences were not significant, with treatment responses being both lesser and greater than the Untreated (NIL), although consistent with the Amira trial, T4 timing had greatest yield. Thousand grain weight was significantly greater than Untreated in T3 and T4 treatments.
Harvested seed contained sclerotia, ranging from 0.2-1% of grain weight. Differences in sclerotia were not consistently related to fungicide application in this trial.
|Treatment||Main stem/branch lesion||Stem base lesion||Main spike lesion|
|T1 + T3||10.0||10.8||1.7|
|Treatment||Yield (t/ha)||Grain weight (g/1000)||Protein (%)||Sclerotia (% weight)|
|T1 + T3||2.61||153.4||30.1||0.23|
There were no obvious impacts of fungicide on plant growth or health. Yield responses do not indicate any negative effect of fungicide, in fact in both varieties the double spray treatment is equivalent or greater than the Untreated.
These preliminary results indicate that fungicide known to be effective against sclerotinia in other crops (for example, canola) can reduce but not eradicate incidence of the disease in lupins, particularly on the pods and flower spike.
Stem base infection and lodging did not respond to fungicide application. Disease on upper stems and pods may be greater in lodged plants, later spray timings may be more effective in these cases.
Anthracnose and phomopsis were both present on stems and pods of Amira in this trial, additional benefit from impact on these off target diseases may increase yield benefits from fungicide application, particularly from later timings.
While in other crops timings at the start of flowering appear most effective, these trials tend to show responses across a range of timings around full flowering on the main stem.