2018-19 soybean on grey soil, Bundaberg

Posted in PulseCheck–Coastal on Mar 12, 2019

2018–19 summer: Soybean on grey soil, Bundaberg

Grower: Chapman Family. With 20 years experience with soybeans Tony does his own crop monitoring, ably assisted by his son Mitch.

Farming system: The Chapmans run all farming operations, including the soybeans, under a controlled traffic and zonal tillage system. They follow a 5-year rotation of plant cane + 3 ratoons followed by either peanut or soybean, then field pea before returning to plant cane in spring.

Location: Calavos, Bundaberg

Monitored area: 20 ha irrigated block, grey soil

Pre-plant preparation

  • 23 October 2018 – cane harvested. Cane stool was removed using a zonal tillage implement to cultivate the bed area (1.2 m) only. Knockdown (RoundUp – Group M glyphosate) herbicide applied to control volunteer cane and broad spectrum of weeds.

Zonal tillage implement – discs, coulter, ripper and roller.

Weeks 1–3 weeks

Management notes:

  • 10 December 2018 – A6785 soybeans direct drilled into the beds at a sowing rate of 450,000 seeds per ha. Good soil moisture profile. Four rows per bed, 280 mm apart. Controlled traffic, wheel spacing 1.83 m.
  • 12 December 2018 – Post-plant pre-emergence herbicide application of knockdown (Grammoxone – Group L paraquat) and residual (Dual Gold – Group K s-metolachlor) for early weed control.
  • 26 December 2018 – Top-dressing of soluble fertiliser – sodium molybdenum, zinc and urea.

Week 4

Management notes:

  • 31 December 2018 – Vezir herbicide (Group B imazethapyr) applied to control emerging weeds and to provide residual control.
  • 3 January 2019 – low pressure overhead irrigation.
  • Tony is monitoring heli size and numbers and considering a Vivus Max spray as the crop begins to flower.

Week 5

Management notes:

  • Ratooning cane and grass weeds emerging through the soybean crop are being monitoring to time a Verdict herbicide spray
  • A moderate amount of leaf damage was observed and a few Heliothis, as well as a small number of silverleaf whitefly.
  • The crop canopy on the beds is starting to close, which will crowd out emerging weeds.
  • Flower buds are developing.
  • An irrigation is scheduled for the coming week as well as continued monitoring for flowering and heliothis for correct timing of Vivus Max.

Flower buds forming

Week 6:

Management notes:

  • A significant amount of leaf damage was observed as well as several stages of Heliothis and a small population of silverleaf whitefly.
  • The crop canopy has almost closed over the beds, which has slowed the growth of ratooning cane and grass weeds in some areas.
  • Flower buds are still developing with several more axillary buds appearing this week.
  • An irrigation has been completed within the last 48 hours.
  • This coming week Tony plans to spray Vivus Max for the heliothis, which have exceeded the threshold, as well as a post-emergence grass herbicide (Verdict) before the canopy completely closes in.

Helis are causing economic damage and will be treated this coming week with Vivus Max.

Week 7

Management notes:

  • The crop was observed to have an abundance of biology this week including both pests such as Heliothis, whitefly and few redbanded shield bugs, and predators such as ladybugs and spined predatory bugs.
  • Several moths were observed however could not get close enough to identify them.
  • A significant amount of leaf damage was observed as well as several stages of Heliothis and a significant population of silverleaf whitefly.
  • The crop canopy has crowded out the space between rows and very few weeds are seen emerging.
  • Flowers are close to emerging with the buds opening slightly.
  • An irrigation is currently being completed.
  • This coming week Tony has planned to spray Vivus Max for the heliothis which have exceeded his threshold and continue to irrigate as much as possible.

Spined predatory bug and victim.

Week 8

Management notes:

  • Crop appears green and healthy with moderate leaf chew from previous heliothis damage.
  • The crop was observed to have predators such as ladybugs including nymph and pupae stages and spined predatory bugs.
  • The heliothis that were observed appeared to be quite sick from the application of Vivus Max and molasses applied over the last week.
  • Other pest species observed were a significant amount of white fly, a small number of loopers, what looked like a newly hatched egg row of spined predatory bug, monolepta in hot spots, and a moderate number of unidentified moths throughout the crop.
  • Apical and axillary flowers have emerged, and bees were observed pollinating these flowers.
  • An irrigation is scheduled for next week with the hope some rain might fall as well.

Week 9

Management notes:

  • Crop appears green and healthy with moderate leaf chew from heliothis damage.
  • The crop was observed to have a large population of predators such as ladybugs, including nymph and pupae stages, hoverfly and larvae, and spined predatory bugs with a moderate population of new hatchings observed as well as unhatched egg rafts.
  • Moderate population of heliothis observed, most of which were quite slow moving from Vivus Max ingestion, with a few small individuals still quite active.
  • Other pest species observed were a significant amount of white fly, a small number of loopers, a moderate population of monolepta in spots, and a moderate number of unidentified moths throughout the crop.
  • Pods are forming and flowering has mostly ceased.
  • February 7th an irrigation was passing over the crop at time of inspection.
  • A post emergence herbicide application (Verdict) will be applied this week to control the grass and ratooning cane weeds in the crop.

Spined predatory bug unhatched egg rafts

Week 10

Management notes:

  • There are large flights of Grass Blue Butterflies flying around in the canopy, laying eggs on flowers. A spray to control emerging grubs from these eggs may be required in the coming week.
  • There are a large number of aphids present but these are being controlled by large numbers of beneficial lady beetles so no treatment is required yet.
  • There are quite a few whiteflies present as well, which is a concern. Numbers will need to be monitored as large numbers can impact plant health and growth and cause sooty moulds to develop on leaves and pods, which can make harvesting difficult.
  • This block has a bit of volunteer cane growing, which may warrant a treatment with Verdict to clean up. This will control grasses as well. Control of volunteer cane will help control diseases and nematodes that can survive on these isolated plants, which infect the subsequent cane crop. It also aids harvesting by removing these large stools, which can end up in the header causing blockages or shattering of beans.

The large number of aphids present are being controlled by large numbers of beneficial lady beetles.

Week 11

Management notes:

  • Evapotranspiration rates of 7-8 mm per day make it a struggle to keep water up to crops in full pod fill.
  • Green Vegie Bug are the main issue now as pods are at a vulnerable stage.

Week 12-13

Management notes:

  • Crop is coping as best it can with the dry weather. Irrigation is occurring on a 7-8-day cycle as we are now in the middle of pod filling.
  • In previous weeks the crop was observed to have a significant population of grass blue butterfly (GBB) towards the end of flowering, no control sprays were given and only few butterflies were observed today.
  • Pests observed included significant populations of green vegetable bug (GVB) in adult and nymph stages, redbanded shield bug in adult and nymph stages and a small population of monolepta in spots.
  • Pods have well and truly set now and are filling nicely. Some pod abortion is occurring, which might be due to the challenging dry weather conditions or as a result of the earlier GBB damage that may have affected the pod development. Very few holes from sucking pests were identified on these aborted pods.
  • Bronzing of the leaves was observed, which could be attributed to sunburn or wind rub.
  • Mitchell plans on spraying the insecticide Decis Options for the control of the large population of GVB.

Pods are setting and filling well

Week 14:

Management notes:

  • Crop is coping as best it can with the dry weather. Irrigation is occurring on a 7-8-day cycle however water available on this farm for irrigation is running very low.
  • An insecticide application of Decis Options and salt was applied late last week to control the growing population of GVB, redbanded shield bugs and monolepta beetles.
  • A significant reduction in pests was observed this week with only few redbanded shield bugs present and a lot of dead and very sick monolepta beetles observed in the wheel tracks.
  • Pod abortion is still occurring throughout the crop, mainly due to the dry weather. There is also varying uniformity of pod filling observed.
  • This week Tony is looking at completing the Verdict application for ratooning cane in the block and hoping for some rain.

Results of an effective application of Decis Options insecticide.

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