Happenings around Katherine Research Station

Monitoring in the irrigated cotton trial at KRS

Insect scouting is a key component of integrated pest management and has been a routine exercise in the KRS cotton trials, along with constant growth measurements and data collection taken in the trial plots. Insect monitoring of whiteflies, aphids, myrids, heliothis and heliothis eggs or larvae, spiders, grasshoppers, lady birds, etc. aims to ensure the numbers stay below threshold populations that trigger chemical control requirements and to keep abreast of the entomology dynamics in cotton.

Heliothis (Helicoverpa spp.) has been identified in only low populations on the new Bolgard 3 varieties, with higher populations detected in the non-bolgard refuge crops. Myrids were found and reached above threshold levels, which did instigate spraying an insecticide targeted at controlling sucking pests. This has been the only requirement to date of pesticide spray throughout this trial. Myrids and Green Vegie bugs damage the cotton bowl at an early stage that can have a major impact on yield and quality.

Many beneficial insects have been found such as wasps, spiders, lady birds and ants which are predatory insects and reduce the numbers of problem pests. It is only another week or so until defoliation occurs and then not long until picking. Feel free to contact us at KRS and come and have a look before the end of this cotton growing season.

Dryland cotton

The dryland cotton trial was planted two weeks earlier than the irrigated cotton and is significantly more established, but the plant growth has been severely restricted due to reduced rain this season. The cotton in this trial will soon be sprayed with a defoliant and “boll cracker” in preparation for harvest within two weeks of application. KRS cotton trials will be hand picked rather than machine harvested due to the small size of the trial plots.

Hay and silage production

Mowing and baling is nearly complete with hay being utilised for the DPIR farm livestock. Native pasture, mixed improved pasture species, sabi grass, and soybean demonstration areas have been utilised for the KRS farm hay program. The casava tops have just been cut with a forage harvester and have been covered with plastic for silage. Tubers will be dug up in the near future, the objective is to investigate the potential of cassava as a feed source for feed-lotted cattle.

Work in the mango orchard

Work in the mango orchard with the dedicated plant industry team never ceases, current trials will show what effect regular pruning has on flowering times.

Potential trial in the "bird exclusion enclosure" at KRS

In early January a cover crop of sorghum was sown to rejuvenate the soils in preparation for future trials to be conducted. The cover crop has just been mulched in for stubble retention and once irrigated all mulch will be ploughed in, rotary hoed and beds formed for a planned ginger and turmeric trial, and a future spice trial – watch this space.

Oats for a rotational crop and weed control

3.3 hectares of oats have been sown and are well established now. This is the second season that oats have been implemented as part of the rotational cropping program, an easy to grow crop that gives the opportunity for controlling broad leave weeds during the off season. The crop will be to be utilised for hay.

Pigeon pea as an insect trap crop

1.2 hectare of pigeon pea (variety Sun Rise) was planted as an insect trap crop for the cotton. This is a requirement of the Bolgard 3 resistance management plan (RPM) stipulated for all Bolgard 3 crops by Bayer. The RPM is based on three basic principles:

1) minimising exposure of Helicoverpa spp. to the Bacillus thuringiensis (Bt) proteins Cry1Ac, Cry2Ab and Vip3A genetically inserted in Bolgard 3 cotton,

2) providing a population of susceptible individuals that can mate with any resistant individuals hence diluting any potential resistance, and

3) removing resistant individuals at the end of the cotton season. These principles are supported by five key components of the RPM:

1. planting restrictions
2. refuge crops
3. control of volunteers and ratoon crops
4. pupae destruction/trap crops
5. spray limitations

This particular variety of Pigeon pea was selected as it is a prolific flowerer for most of the year which makes it very attractive and an excellent trap crop for the insects, pests and beneficials in Cotton.