Budworm Bulletin
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Department of Primary Industries Contacts Michelle Pardy: PO Box 76, Karook St, Cobram, 3644. Ph: 5871 0600 Fax: 5872 1784 BBUUDDWWOORRMM BBUULLLLEETTIINN Information on Native Budworm (Helicoverpa punctigera) activity during 2006 September 5tthh 2006 The following counts are collected using traps that work by attracting male H. punctigera moths using baits that mimic the female moth sex pheremone. The traps are very specific to the native budworm, and as such, provide a pretty good indication to the timing of moth flights from central Australia and how they compare to previous years. Even so, the counts are only valuable as a guide to activity. Moth numbers, and the subsequent generation of grubs, will vary between regions and paddocks, so monitoring remains the best way to determine the risk they pose to individual crops. BUDWORM NUMBERS DURING THE PERIOD AUGUST 23TH- SEPTEMBER 5TH Region Trap Sites Moth count Moth count Crop & Comments Aug 21-29 Aug 28- Growth Stage Aug 28-Sep 4 Sept 4 Rain 0.4-4mm Ultima - 2 lentils not flowering across the Mallee. Walpeup 27 0 Mallee Flowering, Very warm Berriwillock - 23 Lentils – Early flower. temperatures on Werrimul 59 - - Sunday –upto 30°C Faba Beans, some Wimmera Nhill - 12 4 mm rain. flowering North Faba Beans Kerang - 10 - Central Field Peas COMMENTS Trap monitoring began two weeks ago, and while not all traps are operational, reports to date indicate low levels of native budworm moth activity across the Mallee, Wimmera and North Central regions. These counts are well below threshold levels. The low level of trapping suggests that there has not yet been a major inflight of budworm from central Australia. THRESHHOLDS The following Budworm trap thresholds are a guide to the level of moth activity, ie the trap counts required, for one egg to be laid on approximately 5 percent of field pea plants in a crop: Department of Primary Industries Contacts Michelle Pardy: PO Box 76, Karook St, Cobram, 3644. Ph: 5871 0600 Fax: 5872 1784 Northern Mallee: 400 moths (cumulative 10-day moth tally) Southern Wimmera: 180 moths (cumulative 10-day moth tally) Note: The difference between the 2 thresholds corresponds to the generally higher level of moth flight activity in the Mallee, due to the warmer evening temperatures. For other districts, select a threshold that is relative. For example: around Birchip, a reasonable threshold is about 300 moths. Department of Primary Industries Contacts Michelle Pardy: PO Box 76, Karook St, Cobram, 3644. Ph: 5871 0600 Fax: 5872 1784 BBUUDDWWOORRMM BBUULLLLEETTIINN Information on Native Budworm (Helicoverpa punctigera) activity during 2006 September 14tthh 2006 BUDWORM NUMBERS DURING THE PERIOD AUGUST 23TH- SEPTEMBER 5TH Region Trap Sites Moth count Moth count Crop & Comments 7 days 10 day Growth Stage Aug 28-Sep 4 Ultima 64 91 Lentils flowering Walpeup 3 4 Peas, podding 8-22 mm rain. Mallee Berriwillock 105 150 Lentils flowering. Cooler conditions Werrimul 81 115 Lupins finished flowering Nhill 32 45 Faba Beans, flowering 22 mm rain. Ave Wimmera Warracknabeal - 248 Flowering Vetch temp. 20°C North Kerang 18 26 Faba Beans Central Elmore 95 135 Lupins early flowering 15mm rain. COMMENTS Trap operators are beginning to record higher levels of activity around the state. This suggests moths have been carried in from parts of central Australia on recent northerly winds. Activity seems to be highly variable across each region, with Warracknabeal recording 248 moths for the previous 10 day period, while nearby Nhill only recorded 45 moths for the same period. From the 10 day counts, the Mallee remains below threshold, however the high count for Warracknabeal suggests the Northern Wimmera could be approaching threshold in some areas. Thresholds are a guide to the level of moth activity (trap counts) required for one egg to be laid on approximately 5 percent of field pea plants in a crop. When these thresholds are exceeded, growers are advised to be more vigilant for grub activity. For the Northern Mallee, the threshold trap counts are 400 moths (cumulative 10-day moth tally), and for the southern Wimmera, the threshold is 180 moths (cumulative 10-day moth tally). The difference between the thresholds corresponds to the generally higher level of moth flight activity in the Department of Primary Industries Contacts Michelle Pardy: PO Box 76, Karook St, Cobram, 3644. Ph: 5871 0600 Fax: 5872 1784 Mallee, due to the warmer evening temperatures. For other districts, thresholds are relative, ie around Birchip, a reasonable threshold is about 300 moths. Egg Laying Adult moths generally live for between two to four weeks, and they fly between plants, feeding on nectar from flowers and laying eggs on many types of native and introduced vegetation, including broadleafed crops such as field peas, canola, lupins, lentils and chickpeas. Female moths can begin laying eggs just three days after their own emergence, and each female can lay up to 2000 eggs over several days, which explains how grub populations can build up so dramatically! Eggs generally hatch somewhere between 4-21 days depending on temperature, but they can hatch (and develop) more quickly in warmer weather, with larvae sometimes hatching in as little as 3-7 days. However, many eggs will not hatch due to predation from natural enemies or being dislodged from the plant by heavy rain or strong winds. Once on the ground, young hatching larvae are unlikely to survive, so higher moth counts don’t necessarily mean high grub numbers. Department of Primary Industries Contacts Michelle Pardy: PO Box 76, Karook St, Cobram, 3644. Ph: 5871 0600 Fax: 5872 1784 BBUUDDWWOORRMM BBUULLLLEETTIINN Information on Native Budworm (Helicoverpa punctigera) activity during 2006 October 2nndd 2006 BUDWORM NUMBERS DURING THE PERIOD 18TH –24TH SEPTEMBER AND 25TH SEPTEMBER-1ST OCTOBER. Region Trap Sites Moth count Moth count Crop & Comments 18-24th 25th Sep-1 Growth Stage Sept Oct Ultima 0 (trap fell) Lentils flowering Preceeding week Walpeup 0 190 Peas, podding Mallee hot/windy. No Berriwillock 0 276 Lentils flowering. rain. Werrimul 223 Lupins finished flowering Nhill 30 67 Faba Beans, podding Preceeding week Warracknabeal 282 151 Flowering Vetch hot/windy. No Wimmera Brim 347 462 Beans flowering rain. Late crops Wycheproof 246 256 Peas sown late struggling North Kerang 152 73 Faba Beans Central Elmore 195 Lupins still flowering 3.5 mm rain. South West Hamilton 176 223 Peas flowering 22 mm rain Sweepnet counts from 5 lots of 10 sweeps (from flowering onwards) Nandally 24/09/06 - 5 from 10 sweeps in an advanced pea crop. Instar 1-2 Walpeup 24/09/06- 10 small grubs. Instar 1-2 8 grubs in 60 sweeps. Instar 1-3 Wrap up 18th-24th September Department of Primary Industries Contacts Michelle Pardy: PO Box 76, Karook St, Cobram, 3644. Ph: 5871 0600 Fax: 5872 1784 For the week 18-24th September, trap operators recorded high levels of native budworm activity across most areas of the state. Moths were most probably carried in from parts of central Australia on northerly winds during the preceding week. Activity was highly variable with Warracknabeal recording 248 moths for the previous 10 day period, while nearby Nhill only recorded 45 moths for the same period. Activity approached threshold levels in many parts during this period. Wrap up 25th September – 1st October. Trap counts have generally remained high across the state during the past week. From the 10 day counts, parts of the Wimmera (Brim 660) and Mallee (Berriwillock 300) have exceeded thresholds for moth activity. This means that growers will need to be very vigilant in monitoring paddocks for grub activity over the coming weeks. There have been recent reports of spraying in early maturing lentils around Boolite, and Peas and beans in the Nhill area. The dry, warm conditions, coupled recent frost damage, means that growers will need to consider seriously the yield and economic potential of the crop, before proceeding with any spraying activity. Monitoring remains the key to understanding what is happening in individual paddocks. Given the appearance of larvae, the sweepnet now becomes an essential monitoring tool. But how many is too many? The following are insect control thresholds, which describe the number of grubs required to do economic damage to various crops. From GRDC (2001). Crop Average no. of native budworm grubs per 10 sweeps Peas 5 Vetch 6-8 Lentils First sign of activity Lupins 1-2 Faba Beans 2-3 Canola 5-10 /sq m. (larvae >10mm)** ** speculative estimate Tips for Sweeping: • Take sets of 10 sweeps. Repeat 5 times across the paddock. Each set of 10 sweeps should be taken from different representative areas of the crop. • For each set of 10 sweeps, count the number of larvae collected and record their size. After 5 sets of sweeps calculate the average number and size of larvae. • If crops are podding it is worthwhile to determine if grubs are burrowing into pods or not. Collect 20 pods as you sweep, split these and check for damage. Department of Primary Industries Contacts Michelle Pardy: PO Box 76, Karook St, Cobram, 3644. Ph: 5871 0600 Fax: 5872 1784 BBUUDDWWOORRMM BBUULLLLEETTIINN Information on Native Budworm (Helicoverpa punctigera) activity during 2006 October 16tthh, 2006 BUDWORM NUMBERS DURING THE PERIOD 9TH –15TH OCTOBER Region Trap Sites Moth Crop & Comments 10 day count Growth Stage Preceeding week Walpeup 0 Peas, 90% ready to harvest Mallee hot/windy. No Berriwillock 0 Lentils sprayed 3/10 rain. Warracknabeal 481 Vetch - stressed Hot/windy Wimmera Brim 452 Beans - very stressed. weather Wycheproof Peas sown late North Kerang 162 Faba Beans Central Elmore 20 Lupins still flowering Dry South West Hamilton 70 Peas flowering 22 mm rain Wrap up 2nd –15th October Trap moth counts remain high across much of the Wimmera, whist numbers are variable across other parts of the state.