There are increasing areas of cotton grown in regions which are prone to cool seasons, eg. the Darling Downs, the upper Namoi and upper Macquarie valleys. Farmers even further south in the Lachlan valley are also now showing interest in cotton production and, given good management and suitable varieties, there appears no reason why they should not be successful. In all these more marginal areas an early maturing crop is highly desirable.

The major Australian cotton yarn spinners are encouraged by the improvements the researchers and the growers have managed to obtain in the newer varieties. Increased fibre strength has given increased yarn strengths (particularly in rotor spinning), which . generates improved fabric strength, and improved fabric production performance and efficiencies. The production of a finer, more mature fibre has also allowed the spinners to produce finer yarns than was possible before on the rotor spinning system.

The actual decision regarding which seed variety to plant had to be made some months -ago by growers through CSD, this decision is mostly based upon a number of factors, viz: 1: Yield 2: Resistance to insects and disease, such as bacterial blight 3: Quality of fibre The above are listed in order of importance to the grower. As a marketer I would like to move the order to place fibre quality into first place; however, I recognise that economics and the ability to make higher yield, consistent with quality, has to be of first importance

This Overview has been compiled after talking with a limited number of growers from most districts, and as could be expected there were some opposite opinions expressed. However I will talk about the most commonly expressed opinions and make brief comment about the opposite view where appropriate.

Seedling diseases include seed rots, pre and post emergent damping 9ff and root pruning. Numerous fungi can be responsible although Rhizoctonia sp., Pythiwn spp. and Fusarium spp. are the most important. It is sometimes difficult to separate seedling diseases from the effects of insects such as wireworms and herbicide damage. These other factors can also interact with the seedling disease pathogens to result in poor stand establishment and the costly need to replant.

You are all aware that currently there are three varieties available commercially: Siokra 1-2, Sicala 3-1 and DP90 (Deltapine - Acala) . Among these three, Siokra with its okra leaf, is very distinct from the other two with their normal shaped leaves. Siokra is also distinguished by it's vigour in genninarion and establishment, it's heavy production of fruiting forms and it's small, storm resistant bolls. Although Siokra doesn't usually flower any earlier than Sicala or DP90 its crop matures earlier, and it's okra leaves confer some resistance to pests especially mites. It is also practically immune to Bacterial Blight which causes severe damage in susceptible varieties. Siokra yields well under a range of planting dates and sowing conditions but does tend to lodge with a heavy crop leaving it vulnerable to boll rots and perhaps Alternaria, while it also at times suffers "premature senescence" with earlier than expected "cut-out" of either sections or the whole of the crop.

The Siratac system when it was originally conceived had no database system included in the workings of the system. On beginning to use the system however data which was accruing on individual management units could be seen to be of use to the industry as a whole. Staff of the CSIRO then set about constructing a database to allow access to the data stored on individual management units. Since the development of this database it has been used by researchers and Siratac staff for a number of uses which include:

SIRATAC users have the option early in the season of using standard thresholds or dynamic thresholds which vary between the standard level and an upper limit. Thresholds are increased if the crop is early and there will be no yield loss. If the crop is late, or if a yield loss would occur> then thresholds are reduced to base level. Dynamic thresholds aim to maintain yield and quality while avoiding unacceptable harvest delays and normally reduce the number of early season sprays by one or two. However, early crop protection is still a controversial subject within the cotton industry, and most growers do not use the dynamic option within SIRATAC.

To understand, and predict, Heliothis dynamics on cotton, along with changes in resistance levels, we must understand their dynamics on other hosts and the patterns of movement from these to cotton. The level of complexity is too great to consider conceptually and so a simulation model is necessary.

The aim of the present work is to assess the usefulness of pteridines in determining the age of adults of P. scutigera. Major practical results are outlined in the following sections - detailed procedures and data will appear elsewhere.