Budworm Bulletin

Budworm Bulletin. Number 1. September 24, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 1. SEPTEMBER 24, 1997 (3 PAGES) From Melina Miles & Barry Robinson. VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

WELCOME TO ANOTHER SEASON OF BUDWORM WATCH.

The outlook for 1997 The prediction for native budworm in the coming season is for average to below average numbers in most areas. There are large breeding populations in Western Australia and smaller populations in south western Qld/NSW. During September conditions have been suitable for the migration of moths from both WA and Qld (prevailing westerly and northerly winds associated with the passing of frontal systems across southeastern Australia). Trap catches in the Mallee indicate that we are getting moths from both these sources, but the migration into the Wimmera has been less evident.

Significant flights of moths into the mallee Native budworm moths have been present in the north west cropping region for over a month, but traps have been operating in the Mallee and Wimmera only since the beginning of September. In that time there have been significant flights of moths into the Mallee on several occasions (see table), but large flights of moths are yet to be recorded in the Wimmera.

Trap site Crop Total moths for 10 Stage of crop days (10 Sept-19 Sept) development Woorinen (NW of Swan Hill) canola 674 flowering Ultima (SW of Swan Hill) vetch 234 vegetative Ultima faba beans 2220 flowering Swan Hill chickpeas 321 vegetative Swan Hill field peas 132 vegetative Birchip field peas 34 vegetative, early flowering Brim field peas 10 early flowering Dooen (NE of Horsham) canola 102 flowering Dooen faba beans 74 flowering Polkemet (NW of Horsham) field peas 8 vegetative Quantong (W of Horsham) faba beans 24 vegetative

There is a marked difference in the numbers of moths caught in flowering and non-flowering crops. Native budworm moths are attracted to flowers to feed. Female moths require nectar for energy to fly and mature eggs, therefore moths will move preferentially into flowering crops. As a result, trap catches are higher in flowering crops, and more indicative of subsequent budworm infestations in podding crops. Budworm Bulletin No.1, September 24, 1997

Why use a 10-day tally? Daily fluctuations in moth trap catches make it difficult to interpret how large, or small, the moth population in a district is likely to be. Research undertaken by Department entomologists over the last 5 years has shown that there are a number of factors that affect trap catches. For example, weather conditions, particularly evening temperatures; the number of flowering crops nearby; the presence of flowering weeds such as oxalis or capeweed. After studying the relationship between trap catches and the number of eggs laid in crops for 5 years the entomologists found that using a 10-day running tally of moth numbers provided the most meaningful measure of egg laying.

The following thresholds are devised to provide a rough guide to a level of moth activity likely to result in one egg being laid on approximately 5% of field pea plants:

Northern Mallee: cumulative 10-day tally of 400 moths Southern Wimmera: cumulative 10-day tally of 180 moths

The difference between the thresholds is to account for the generally higher level of moth flight activity in the Mallee, probably because of the higher night temperatures. In practice this means that although twice as many moths may be caught in Mallee traps, the number of eggs laid in crops in the Mallee and Wimmera may not differ significantly.

Select a threshold between the extremes that is appropriate for your district. For example, if you are at Birchip you would use a threshold of around 300.

It should be remembered that high levels of moth activity does not always result in large numbers of larvae (caterpillars). Eggs and young larvae can be dislodged from plants by rain and wind. There are also a large number of insects which prey on native budworm eggs and early instar larvae (caterpillars). For example, ants, lacewings, wasps and predatory beetles can have a big impact on the resulting budworm population.

Egg numbers in Mallee crops Egg-laying is occurring in flowering crops where significant numbers of moths are being caught. However, the rainfalls over the past fortnight have reduced the number of eggs surviving on the plants. In monitored paddocks, up to 25% of plants have had eggs, but these percentages have been reduced following rain.

As yet there is no evidence of major larval populations in flowering or podding crops. Given the timing of moth flights and egg laying it will be 5-10 days before larvae start to emerge (based on historical average temperature data for Swan Hill).

Overview of the Wimmera Although there have been suitable conditions for migration, the numbers of moths caught has been low, even in flowering crops. As yet there is no indication that there is significant egg-laying in crops.

OTHER ISSUES Aphids in cereals, pulses and canola In spring, aphids typically start to invade crops from neighbouring weeds. The infestations are usually confined to the crop margins, but will occasionally become more widespread through the crop.

In pulses, cowpea aphids tend to colonise the growing points and early infestations can be difficult to detect. In canola the flowering head is infested.

In cereals, infestations of oat aphids colonise the base of the plants, and corn aphids the leaves and leaf whorls. The direct impact of aphids is difficult to measure, and aphids do not have an impact on yield unless the population is large, or present on the plants for an extended period. Barley Yellow Dwarf Virus (BYDV) can cause significant yield losses when young plants are infected. Transmission of BYDV by spring infestations of aphids has no impact on yield.

2 Budworm Bulletin No.1, September 24, 1997 The important thing to remember with aphids is not to rush in and spray, chemical control is not always warranted with aphids. Unless numbers of aphids are extremely high it is advisable to monitor infested paddocks a second time, about 4 days later, to determine whether the population is continuing to increase in size. Check across the paddock to clarify whether the infestation is restricted to the crop edges, or is more widespread.

In past years, infestations of aphids have declined naturally as the crops start to mature and dry off, later in spring. This occurs as the plants become unsuitable for aphid survival and the aphids either die or migrate out of crops to surrounding weeds and grasses where they survive the summer.

Rain and natural enemies are also important factors in regulating aphid populations. Rain will wash aphids off plants, and reduce numbers. Wasps, ants, lacewings, ladybirds and a range of other insects feed on aphids keeping the populations under control. Generally aphids only become major problems when conditions are warm and dry, plants are under moisture stress, and the activity of natural enemies is hampered by unsuitable climatic conditions or the application of insecticides.

INSECT PEST IDENTIFICATION BROCHURES Guides to the key insect pests of cereals, pulses, canola, pasture and false wireworm

Agriculture Victoria has recently released a set of insect identification brochures for grain growers and their advisers. The set of five brochures have full colour pictures of the major insect pests and recommendations for sampling, action thresholds and information on pest lifecycles.

The brochures are free and available from Agriculture Victoria offices or Agriculture Victoria, VIDA, Horsham. For your copies phone 03 53622 111.

3 Budworm Bulletin. Number 2. October, 1, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 2. OCTOBER 1, 1997 (2 PAGES) From Melina Miles & Barry Robinson. VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

MOTH TRAP CATCHES FOR THE 10 DAYS 17-26 SEPTEMBER, 1997

Trap site Crop Total moths for 10 Stage of crop days (17 Sept-26 Sept) development Mallan, NSW canola 179 flowering Woorinen (NW of Swan Hill) canola 307 flowering Ultima (SW of Swan Hill) vetch 157 vegetative Ultima faba beans 887 flowering Swan Hill chickpeas 125 vegetative Swan Hill field peas 62 vegetative Goschen (SW Swan Hill) field peas 90 flowering Dumosa field peas 152 (22-26 Sept) flowering Birchip field peas 5 vegetative, early flowering Brim west field peas 10 early flowering Dooen (NE of Horsham) canola 118 flowering Dooen faba beans 89 flowering Polkemet (NW of Horsham) field peas 2 vegetative Quantong (W of Horsham) faba beans 29 vegetative

Moth numbers in the Mallee are generally lower than the last 10 day period, but continue to contribute to the build up of eggs in flowering crops.

Surveys of crops around Swan Hill have shown that there are both eggs and early instar (1-2) larvae present in crops. However, larval densities are mostly well below threshold with averages of between 0.5 and 1.5 larvae per 10 sweeps being found. Highest numbers of larvae are again being found in vetch.

In the Wimmera, moth numbers remain low at almost all trap sites, consequently with little egg laying evident. With northerly winds predicted for the next couple of days, and many crop starting to flower, it is possible that higher numbers of moths could be recorded.

PEA WEEVIL NOW ACTIVE (AV Pea weevil agnote available on pollfax as document no 33303) Budworm Bulletin No.2, October 1, 1997 Cumulative day-time temperatures have been high enough to prompt movement of pea weevil from their hibernation sites into crops. Crops sampled in the Wimmera and Mallee, appear to have close to threshold levels of beetles already (2 pea weevil per 25 sweeps). Indications are that the movement into the paddocks has only started recently with most beetles still confined to the crop edges.

Movement of pea weevil is dependant on temperature, therefore they will move into pea crops regardless of whether they are flowering or not. Female pea weevil need to feed on pollen before they can mature eggs, and will only lay eggs on exposed pods. As a result migrants will stop in the edges of flowering crops, but tend to move further into non-flowering crops in search of flowers. The longer sampling or control is delayed past the time of first pea weevil invasion, the more likely it is that pea weevils will have moved beyond the first 5-10 metres of the crop. However, unless the crop is very late, it is unlikely that the pea weevils will move further than 40-50 metres into the crop by the time chemical control is warranted. This slow movement is the basis for the recommendation that only a border spray, of 40-50m, is necessary for effective pea weevil control.

Poor results with pea weevil control, is more often due to the timing of chemical application being either too early or too late, not because the pea weevils have moved beyond the crop border. Remember that the pea weevils will emerge over a period of 1-3 weeks (depending on temperatures) and early spray applications may not control weevils that invade post-spray. Timing of pea weevil control should be based primarily on the development of the pea crop. Only when the flowers drop, and pods are exposed, do pea weevil start to lay eggs. Ideally, chemical control should be applied to kill adult beetles just prior to the first pods being exposed.

APHIDS CONTINUE TO CAUSE CONCERN

Aphids in pulses, pasture and cereals continue to be reported. Large numbers are being found in some of the pulses, particularly vetch.

Photosentisation in sheep caused by aphids A case of photosentisation in sheep grazed on aphid infested vetch has occurred in Nhill. Apparently, aphid produce a chemical that causes the ears, nose and other exposed skin of sheep to become extremely sensitive to exposure to sunlight. DNRE vet, Bob Crawford said that he had not seen such a case since the 1960s when barrel medics were heavily infested with aphids. This case suggests that aphid control may be warranted in a grazing as well as cropping situation.

Aphids in crops - some considerations Aphids usually occur in autumn and spring, if conditions are relatively warm. Weeds provide breeding sites for aphids during early spring and aphids invade crops from surrounding weeds. Initially infestations are confined to crop edges, but as numbers build up they tend to disperse further into the crop.

Measuring the impact of aphids on plant growth or yield is difficult. As a consequence there are few comprehensive control thresholds for aphids. Essentially they reflect the opinion that aphid infestations are of economic concern only when they are widespread across the paddock, infesting at least 20-50% of plants. Available thresholds are as follows: 1. Cereals (WA): 10-20 aphids on 50% of tillers. Infestations not considered economic to control in crops expected to yield less than 3 t/ha. 2. Cowpea aphids in faba beans: 10% of plants heavily infested. 3. Canola: at least 20% of plants with 25mm of stem infested.

Aphid feeding can impact on plant growth, seed set and grain-filling. The timing and duration of the infestation determines which component is most affected.

Rain, a range of predators and parasites (ladybirds, wasps, hoverflies and lacewings for example) will control or reduce the number of aphids to some extent.

2 Budworm Bulletin. Number 3. October, 8, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 3. OCTOBER 8, 1997 (3 PAGES) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

MOTH TRAP CATCHES FOR THE 10 DAYS 24 SEPT - 3 OCT, 1997

Trap site Crop Total moths for 10 days (24 Sept-3 Oct) Mallan, NSW canola 331 Manangatang field peas 285 (2-3 Oct) Woorinen (NW of Swan Hill) canola 160 Ultima (SW of Swan Hill) vetch 406 Ultima faba beans 702 Swan Hill chickpeas 56 Swan Hill field peas 148 Goschen (SW Swan Hill) field peas 786 Dumosa field peas 417 Birchip field peas Brim west field peas 291 Dooen (NE of Horsham) canola 94 Dooen faba beans 100 Polkemet (NW of Horsham) field peas 25 Quantong (W of Horsham) faba beans 51

Moth numbers were low until the nights of the 1st and 2nd of October, when large flights were recorded in the Mallee, and moderate flights recorded in the Southern Mallee and Wimmera. The large flights occurred in conjunction with the passage of a cold front and a period of pre-frontal north-north westerly winds, bringing moths down from areas in western Qld/NSW and possibly eastern WA.

THERE ARE NATIVE BUDWORM CATERPILLARS IN MALLEE CROPS

First to third instar larvae have been found in Mallee crops monitored over the last week. However, caterpillar numbers are still below threshold numbers in most crops. The highest larval densities of 3 larvae per 10 sweeps were in faba beans that had been flowering for 2-3 weeks. Larval numbers in later flowering crops of peas, chickpeas and vetch are significantly lower.

In the Wimmera Budworm Bulletin No.3, October 8, 1997 The moth numbers in the Wimmera have only in the last 10-day period approached the threshold of 180 moths over 10 days. As yet no significant populations of budworm larvae have been found in Wimmera crops.

Start monitoring crops Flowering and podding crops in the Mallee should be monitored to determine if there are populations of larvae, and an assessment made of the average density of larvae. Because the density of budworm larvae is highly variable between paddocks, it is important to sample more than one paddock per farm, and preferably sample each individual paddock to accurately assess the budworm situation in each.

Monitoring for native budworm Effective management of native budworm depends on regular crop monitoring that provides information on how many native budworm caterpillars are in the crop and at which stages of development. As budworm larvae develop they consume more plant material. Leaf material does not provide sufficient protein for later instar larvae, hence third instar and older larvae will readily burrow into pods and feed on developing grain. It is these third, and older, instar larvae that cause economically significant crop losses.

Regular monitoring (at least weekly) with a sweep net is the easiest way to monitor pulse crops for native budworm. Take sets of 10 sweeps from 5-10 sites across the paddock. After each of the 10 sweeps inspect the catch, recording the number and size of the larvae caught. After the 5-10 samples have been taken and recorded, average the number of larvae caught for all samples (eg. for 5 samples: (2+1+0+3+1)=7; 7 divided by 5 = 1.4 larvae). The suggested action thresholds for pulse crops are given below:

Because pulse crops differ agronomically as well Crop Control threshold as market price there are different thresholds for (average number of larvae each crop. Most of the thresholds listed below per 10 sweeps) have not been rigorously tested in the field and Chickpeas may be revised after further research (these are Kabuli type 2-3* indicated by an *). Desi type 5* Faba beans 2-3 Caterpillar size is important when determining Lentils 1-2* what rate of chemical is necessary - refer to your Field peas 5 records of larval size and read the insecticide Vetch 6-8* label.

Distinguishing native budworm from other caterpillars Native budworm caterpillars have lumpy skin with dark hairs. Few other pest caterpillars have rough skin. There are a number of caterpillars other than native budworm that may be caught when sweeping pulse crops, particularly in faba beans and lentils. Most of these other caterpillars are loopers, distinguished by the absence of ‘legs’ in the middle of their bodies, and moving with a looping action (see below). Loopers are predominantly leaf feeders, and cause minimal crop damage unless they occur in extremely high numbers. Control of loopers is rarely warranted, so these larvae can be ignored in sweep net samples.

Compare this looper with the native budworm caterpillar pictured on the Bulletin letterhead.

APHIDS, APHIDS, APHIDS, APHIDS.....

2 Budworm Bulletin No.3, October 8, 1997 With warm, dry conditions persisting in most region, aphid numbers continue to increase. In many pulse crops aphid numbers have doubled over the last week. Vetch appears to be the most heavily attacked by cowpea aphid. The numbers of blue-green aphids and cowpea aphids in lentils are also causing concern.

As mentioned in last week’s bulletin, measuring the impact of aphids on plant growth or yield is difficult. As a consequence there are few comprehensive control thresholds for aphids. Essentially they reflect the opinion that aphid infestations are of economic concern only when they are widespread across the paddock, infesting at least 20-50% of plants. The thresholds that are available are: 1. Cereals (WA): 10-20 aphids on 50% of tillers. Infestations not considered economic to control in crops expected to yield less than 3 t/ha. 2. Cowpea aphids in faba beans: 10% of plants heavily infested. 3. Canola: at least 20% of plants with 25mm of stem infested. 4. Lupins (WA): 5 aphids per plant, 30% of plants infested.

As a rule of thumb, control may be warranted in vegetative, to early flowering pulse crops with 15-30% of plants infested. The important thing to remember with aphids is that populations can build up or decline very rapidly. Therefore, unless the population is high at first inspection, it is worth returning to the crop in 2-4 days to reassess the population before making any decisions about chemical control, particularly if rain is forecast in the next day or so.

It is also important to consider chemical choice when controlling aphids. Most of the products available for aphid control are broad spectrum insecticides, which kill natural enemies as well as aphids. Pirimicarb is a selective insecticide which kills aphids, but not the predators and parasites. Natural enemies are powerful allies, capable of controlling moderate populations of aphids.

It is possible this season that aphid populations could build up again after chemical control. Many infested crops are still vegetative or flowering, and will be susceptible to aphids for several weeks. Because of the possibility of further aphid invasions post spraying the following should be considered when making decisions about aphid management: 1. An aphid-specific insecticide will preserve beneficial insects (ladybirds, lacewings, wasps, spiders etc) which will help control any subsequent infestations of aphids. 2. Any crops sprayed for aphids now should be monitored regularly for the remainder of the season to ensure subsequent infestations do not go undetected. 3. Aphids are often difficult to find on plants. Look around the bases of cereal plants, under leaves and in leaf whorls. In pulses look for aphids clustered in terminals, flowers and around basal leaves. To get an estimate of aphid numbers beat plants onto a piece of paper or hand and count. 4. Aphid infestations often spread from the edges of paddocks. To get an overall picture of paddock infestation check for aphids well into the paddock. It may be possible to control early infestations with a border spray.

PEA WEEVIL With the warm weather, the majority of the hibernating pea weevil population will have moved into crops. Because pea weevil movement is triggered by temperature, and not the appearance of flowers in the crop, even vegetative peas will have pea weevils already in them. However, it is recommended that any chemical control of pea weevil is delayed until about the time the first flowers are shed. Delaying the spray as long as possible ensures that the maximum number of pea weevil are in the crop, thereby minimising the risk of subsequent infestations post spraying.

The action threshold for pea weevil is 2 per 25 sweeps. Where crops are relatively late, it is more likely that pea weevil will have moved further into the crop. This season it is important that sweep samples be taken around the crop edges, and further into the crop to determine whether a border spray will provide effective control, or a whole paddock spray is necessary.

More comprehensive information on pea weevil is available in an Agriculture Victoria Agnote. The Agnote is available from AV offices, the AV internet site or from the pollfax service (document number 33303).

3 Budworm Bulletin. Number 3. October, 8, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 3. OCTOBER 8, 1997 (3 PAGES) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

MOTH TRAP CATCHES FOR THE 10 DAYS 24 SEPT - 3 OCT, 1997

THERE ARE NATIVE BUDWORM CATERPILLARS IN MALLEE CROPS

Compare this looper with the native budworm caterpillar pictured on the Bulletin letterhead.

APHIDS, APHIDS, APHIDS, APHIDS.....

3 Budworm Bulletin. Number 4. October, 15, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 4. OCTOBER 15, 1997 (2 PAGES) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

MOTH TRAP CATCHES FOR THE 10 DAYS 1 OCT-10 OCT, 1997

Trap site Crop Total moths for 10 days (1 Oct-10 Oct) Mallan, NSW canola 493 Manangatang field peas 894 Woorinen (NW of Swan Hill) canola 134 Ultima (SW of Swan Hill) vetch 703 Ultima faba beans 575 Swan Hill chickpeas 92 Swan Hill field peas 249 Goschen (SW Swan Hill) field peas Dumosa field peas 470 Birchip field peas 224 Brim west field peas 355 Dooen (NE of Horsham) canola 583 Dooen faba beans 528 Polkemet (NW of Horsham) field peas 100 Quantong (W of Horsham) faba beans 76

Moth numbers have been boosted in the past 10 days by a couple of large flights in early October. There were also significant flights of moths into both the Mallee and Wimmera over the weekend, associated with the strong northerlies and westerlies. The large catches from the weekend are not included in the counts above, but some sites caught over 200 moths on Friday and Saturday nights.

The trap catches for the last 10 day period reflect the first significant flights into the Wimmera, taking many tallies over the trap catch threshold of 180 moths. We can expect to start finding numbers of larvae approaching threshold levels in Wimmera crops within the next 2-4 weeks.

In the Mallee there are some crops being sprayed for native budworm. There are two waves of larvae, one set of 3rd and 4th instar larvae, and another of 1st and 2nd instar larvae. The presence of the older larvae in early podding crops warrants monitoring. However, larval numbers are not high. Crops monitored averaged around 1-4 larvae per 10 sweeps. Although there have been several relatively warm days in the Mallee, there Budworm Bulletin No.4, October 15, 1997 does not appear to be pod burrowing by early instar larvae. Monitored crops show low levels of pod damage at this stage.

A NEWISH PEST OF LENTILS - ETIELLA (LUCERNE SEED WEB MOTH)

Over the past couple of seasons there have been Biology: Moths emerge in spring from pupae that lentils delivered with small holes and caterpillar- have survived in the soil over winter. Up to three like damage. The suspected cause of the damage generations breed from spring until the following is Etiella behrii, otherwise known as the lucerne autumn. It is likely that etiella breeds and survives seed web moth, well known to lucerne seed on a large range of legumes, both wild and growers. Etiella has been long recognised as a cultivated. sporadic, and usually minor, pest of all legume Damage: Larvae feed on pods and seeds of crops. However, little is known about etiella as a infested crops. In field peas, lupins and vetch, the pest of lentils. larvae remain within pods until the entire contents are eaten, leaving copious quantities of frass As the area of lentils increases, so to are the number (excreta) and silk webbing behind. In lucerne seed of reports of etiella damage to grain. crops they attack the ripening seed pod, eventually spinning a web which encloses several pods. Description: Etiella larvae grow to between 16 mm and 19 mm long. Newly hatched larvae are cream Etiella damage is easily confused with damage with a black head. In the later stages they develop caused by native budworm. Caterpillars of both a red tinge and several darker red stripes along the pests attack developing seeds, leaving the seed with back. jagged edges or small holes. To distinguish etiella Moths are grey and each forewing has a narrow damage, use a hand lens or magnifying glass to yellow band across the back edge and a white line look for frass and webbing in pods, or on damaged along the front edge. The wingspan is about 20 seed. mm, and the enlarged mouthparts form a prominent snout. First catches of etiella for 1997 A number of light traps have been operating around the Wimmera for the past 4-6 weeks in an attempt to identify initial flights of etiella moths. On 1 October, the first moths were detected in light traps in Keith, SA. In the same week one moth was caught in a light trap near Horsham (in lucerne). On 10 October, several moths were caught whilst sweeping a vetch crop near Swan Hill.

It appears that there are etiella active, but at present the numbers are small. Regular sampling will commence in lentils to collect information on egg-laying behaviour and the potential for managing this pest. Adult and larva of Etiella behrii (reproduced from SARDI fact sheet FS51/85)

Earlier issues of the Budworm Bulletin now available on pollfax All issues of the Budworm Bulletin are now available on the pollfax service. The current week’s Bulletin will remain as document number 33301. Earlier issues are available from the following sites: 33311 Bulletin number 1 33312 Bulletin number 2 33313 Bulletin number 3, etc.

2 Budworm Bulletin. Number 5. October, 22, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 5. OCTOBER 22, 1997 (2 PAGES) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

MOTH TRAP CATCHES FOR THE 10 DAYS 7 OCT-17 OCT, 1997

Trap site Crop Total moths for 10 days (7 Oct-17 Oct) Mallan, NSW canola 254 Manangatang field peas 422 Woorinen (NW of Swan Hill) canola 9 Ultima (SW of Swan Hill) vetch 316 Ultima faba beans 79 Swan Hill chickpeas 109 Swan Hill field peas 54 Goschen (SW Swan Hill) field peas 926 Dumosa field peas 697 Dumosa canola 250 Birchip field peas 329 Brim west field peas 401 Warracknabeal field peas 1222 Dooen (NE of Horsham) canola 607 Dooen faba beans 828 Polkemet (NW of Horsham) field peas 128 Quantong (W of Horsham) faba beans 67

Moth catches over the last 10-day period are relatively high. Large moth flights over the 11th-13th contributed the bulk of the moths caught. In the latter part of the monitoring period, moth numbers were low at most sites.

In the Mallee The number of moths caught in the Mallee is declining, probably as the crops finish flowering. In Mallee crops there are larvae at all stages of development. Sixth instar larvae, from eggs laid in mid September are now reaching maturity. Crops with these later instar larvae are showing signs of pod damage, but in most monitored crops damage levels are still tolerable. Many crops in the Mallee are now moisture stressed and concerns about their ability to fill grain and finish the season have a significant impact on decision-making about budworm control, more about that later in the Bulletin. In the Wimmera Budworm Bulletin No.5, October 22, 1997 The moth flights into the Wimmera over the past 3 weeks have contributed to egg-laying populations and consequently larvae are now being found in most legume crops. However, numbers of larvae remain below threshold levels in most crops. There are 3-5th instar larvae in some crops, but as yet there is little pod damage evident. With the appearance of these later instar larvae, it is important that crop monitoring start in earnest. Thorough monitoring and decisions about control based on monitoring results are increasingly important in a season where yields may be average to below average.

Making decisions about control Action thresholds for insect pests are based on the relationship between: • potential damage caused by the pest & pest density • the expected yield of the crop • the market value of the crop • the cost of chemical control In making decisions about the need for chemical control it is essential that the cost of control be considered in relation to the expected crop return with and without control. As potential yields decline, gross margins also decrease, as a result it becomes more important to ensure that the costs and benefits of spending additional dollars on the crop are examined carefully.

A couple of examples of the relationship between these factors are presented below to illustrate the processes in making decisions about chemical control. Figures used are ‘ballpark’ and intended only as an illustration. Calculations for a 100 ha paddock.

Crop Expected Nett income Nett income Cost of Yield loss yield (t/ha) on grain (excl. control using that equals (gross- variable a synthetic cost of freight) costs) pyrethroid control ($/t) ($/ha) ($/ha) Field peas 2 200 400 15 3.75% 1 200 200 15 7.5% 0.5 200 100 15 15%

What this table illustrates quite clearly is that as yield (and consequently the crop value) declines, the level of pest damage that can be tolerated increases. Although 15% crop damage may be extremely visible in a low yielding crop, it will cost the same to spray as not to spray, therefore there is no economic benefit of spraying, unless crop damage exceeds 15%.

Etiella update Light traps in the Wimmera have not caught further Etiella. Mallee vetch in which etiella moths were found have not continued to yield significant numbers of moths. Monitoring is continuing in the Wimmera.

Other late season pests Armyworm moths are being caught in low numbers in light traps, and have been for several weeks. The numbers currently being caught are unlikely to pose a threat to crops.

Native budworm in lentils, linseed and safflower There has been no work on these crops done in Victoria. We have no research data on budworm in lentils, but given the relative value of this crop a speculative threshold of 1 larvae per 10 sweeps is suggested.

Thresholds for budworm in linseed and safflower are available from Queensland work and are as follows: Linseed: examine 30 plants across the paddock; if 5 or more medium sized larvae are found on 30 terminals or bolls, control is warranted Safflower: examine 30 plants across the paddock; if there are 10 small-medium larvae found on 30 terminals, control is warranted.

2 Budworm Bulletin. Number 6. October, 29, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 6. OCTOBER 29, 1997 (2 PAGES) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

MOTH TRAP CATCHES FOR THE 10 DAYS 15 OCT-24 OCT, 1997

Trap site Crop Total moths for 10 days (15 Oct-24 Oct) Mallan, NSW canola 48 Manangatang field peas 72 Woorinen (NW of Swan Hill) canola 16 Ultima (SW of Swan Hill) vetch 10 Ultima faba beans 39 Swan Hill chickpeas 39 Swan Hill field peas 29 Goschen (SW Swan Hill) field peas 102+ Dumosa field peas 675 Dumosa canola 126 Birchip field peas 45 Brim west field peas 62 Warracknabeal field peas 434 Dooen (NE of Horsham) canola 185 Dooen faba beans 389 Polkemmet (NW of Horsham) field peas 69 Quantong (W of Horsham) faba beans 13

As crops is the Mallee finish, moth flights are no longer important indicators of likely crop damage. Most crops will have dried sufficiently to prevent further pod damage from larvae already in the crop. Native budworm larvae tend to burrow into pods as they develop from third instar on. However, the larvae do not have the capacity to chew through dry, hardening pod walls.

Crops that are completely dry are unlikely to incur further damage, and only younger, green pods that will not yield will continue to support larvae. Although larvae may still be found in drying pulse crops, they are of little significance in terms of impact on yield and are likely to complete development soon. Therefore, it is uneconomic to spray crops that have started to turn and will be completely dry within the next week. In the Wimmera, many crops are still flowering and podding, and native budworm monitoring remains an important part of budworm managment. Larvae resulting from further flights are unlikely to reach potentially damaging stages before the end of the season, but where paddocks have not been sprayed for either aphids or Budworm Bulletin No.6, October 29, 1997 pea weevil there may be late instar budworm larvae present. These crops should be monitored and sampled to estimate the abundance and age of budworm larvae.

Just a reminder that budworm numbers can vary quite significantly between crops and paddocks, therefore it is important to make the decision to spray a paddock based on sampling information from that paddock, and not a nearby crop or paddock.

Larval numbers in pulse crops in the Horsham area are generally below threshold numbers. Just to recap the current thresholds for the different crops

Crop Control Threshold (average number per 10 sweeps) Field peas 5 lentils 1-2* vetch 3-4* faba beans 2-3 chickpeas-kabuli 2-3* chickpeas - desi 5* * indicates control thresholds that have not been developed from field-based research. These thresholds are speculative, and represent a ‘ball park’ estimate essentially based on the relative value of the crops.

Native budworm in canola As yet there have been few reports of damaging numbers of larvae in canola crops. This is probably a consequence of the relatively low numbers of larvae. Preliminary research in 1996 suggested that control was rarely warranted, particularly in lower yielding crops, even when pod damage was evident.

Think about pea weevil at harvest There are several issues and tactics to consider at harvest that can be of benefit in terms of minimising pea weevil carryover in the paddock, and grain losses in the silo. 1. Where infestations of pea weevil have occurred in the paddock, select seed for sowing from well into the paddock. Seed from paddock edges is more likely to be infested with pea weevil, and germination of this grain will be less reliable than uninfested grain. 2. Fumigate infested grain immediately after harvest. Live pea weevil larvae will continue to develop in untreated stored grain, resulting in grain weight reductions of up to 20%. 3. Crop residues should be cleaned up with sheep where possible. Pea weevil in peas will not survive if stubbles are grazed to expose peas to heat and light. 4. Harvesting peas early and then fumigating will minimise the number of pea weevil carrying over around the farm.

Aphid update Aphids are persisting in many of the pulse crops in the Wimmera. In particular, lentils are supporting large numbers of blue green and cowpea aphids. Cowpea aphids are more obvious, clustering on terminals. Blue green aphids appear to feed lower down on the plants under leaves and on stems. Although aphid numbers appear high, crops are continuing to flower and pod. Large numbers of parasitic wasps, lacewings, ladybirds and spiders are keeping aphid numbers under control in some crops.

Small pockets of aphids are being reported in canola, but few major infestations are resulting from initial infestations. Aphid infestations in podding canola is less important in terms of impact than in flowering crops. Late, terminal pods that will not fill before crops mature can support heavy infestations of aphids without adversely affecting yield or quality of older pods.

2 Budworm Bulletin. Number 7. November 5, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 7. November 5, 1997 (2 PAGES) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

THIS WEEK’S MOTH TRAP CATCHES

Trap site Crop Total moths for 10 days (22-31 Oct) Woorinen (NW of Swan Hill) canola 10 Ultima (SW of Swan Hill) vetch 2 Ultima faba beans 17 Swan Hill chickpeas 41 Swan Hill field peas 0 Goschen (SW Swan Hill) field peas 20 Dumosa field peas 298 Dumosa canola 110 Warracknabeal field peas 215 Dooen (NE of Horsham) canola 154 Dooen faba beans 291 Polkemmet (NW of Horsham) field peas 90 Quantong (W of Horsham) faba beans 13

Thanks to all Budworm Watchers! As the season draws to a close in the Mallee, we would like to thank the Budworm Watchers in these areas for their dedication over the past 6-8 weeks. Without your contribution it would not be possible to gather the region-specific data on moth flights. Thanks again.

Moth flight information For the Wimmera growers there is still a little way to go this season, particularly with the rainfall over the past week encouraging many of the pulses back into flowering, and hopefully pod filling.

The number of moths caught in traps is practically insignificant in the Mallee, to some extent an indication of the unsuitability of the crops for egg-laying. As mentioned last week, further flights of moths are of no consequence in senescing crops where the pods have dried and hardened.

Outlook for the Wimmera Budworm Bulletin No.7, November 5, 1997 The development model (DARABUG), uses average historical temperatures to calculate the rate of development of native budworm larvae. Using DARABUG we can predict which flights of moths have the potential to develop into damaging populations of 3rd instar (and older) larvae. According to the model, eggs laid after 30 October will not result in 3rd instar larvae before 30 November. Therefore, flights which occur between now and harvest will not contribute significantly to the budworm population in Wimmera crops.

What needs to be monitored closely from now on are the current populations of budworm larvae in crops.

Average counts of larvae of between 0.1 and 2 larvae per 10 sweeps have been found in lentil and bean crops sampled. Numbers seem to be higher as you go north of Horsham. The majority of larvae are third instar, with a few older. With the information available, and the prediction of DARABUG, it is unlikely that populations will increase between now and harvest, or that there will be significant reinfestations of sprayed crops.

Rain reduces aphid numbers The rain last week has had a dramatic impact on aphid numbers in pulse crops. Aphid numbers have declined significantly, to the point that crops that had been heavily infested are almost aphid free. In addition, the natural predators and parasites that feed on and kill aphids have persisted in large numbers.

The continued presence of these natural enemies means that any surviving aphids will be prevented from multiplying, and further significant infestations are unlikely.

Small numbers of Etiella still being caught in lentil crops Etiella (Lucerne seed web moth) monitoring is continuing in a number of lentil crops across the Wimmera. Small numbers of Etiella moths are being caught in the light traps, and are visible flying in lentil crops. However, it is not possible to determine the potential impact of these small numbers of moths on the crops.

Crop monitoring by AV is being undertaken to try and identify whether Etiella are laying eggs on pods, and whether there are populations of larvae developing. The low numbers of these moths present problems with sampling - it’s a bit like looking for a needle in the haystack!

Because so little is currently known about Etiella, and it still has to be confirmed that Etiella is in fact causing the pin holes and other damage to lentil grain, it is not possible to provide recommendations as to control.

Other ‘pests’ to keep an eye out for

Rutherglen bug (RGB) is a late season pest of canola. As yet RGB numbers appear to be relatively low, but as alternative hosts start to dry out it is possible that larger numbers will move into canola crops. RGB feed on pods and developing grain. They are able to penetrate maturing pods in windrowed crops to feed on seed. The impact of RGB can be reduced seed set, seed quality and viability. Canola crops should be monitored for RGB until harvest.

Stored grain pests, and their management in on-farm storages should be considered prior to harvest. Grain residues in headers, augers and silos can be key sources of these pests. A stored grain pest identification sheet is available from DNRE Horsham and Benalla offices. Contact Peter Botta (Benalla office) for further information on stored grain pest management, decisions on grain protectants and grain storage in general. AV, Horsham: contact Melina Miles or Matthew McCallum ph 03 5362 2111 DNRE, Benalla: contact Peter Botta ph 03 5761 2612.

2 Budworm Bulletin. Number 8. November 12, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 8. November 12, 1997 (1 PAGE) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

MOTH FLIGHTS OVER THE LAST 10 DAYS Moth trap catches have been well below threshold in all Wimmera traps still in operation. This means that there will have been no significant addition to the existing budworm populations in crops. For those who were in the path of the rain and wind on Monday these conditions will have again reduced the number of larvae in the crop.

SITONA WEEVIL ACTIVE Over the last week, large numbers of sitona weevil have been attracted to light traps in the Wimmera. Sitona weevil will attack medics and lucerne. At this time of the year the concern with sitona weevil is infestations of seed and hay lucerne. The weevils emerge from the soil in spring, and are highly mobile, often flying large distances. Large infestations can defoliate lucerne stands.

Sitona weevil are about 5mm long and dark grey-brown with three stripes on the body section behind the head (the thorax). The weevils will ‘play dead’ and drop from plants when disturbed, so finding them can be difficult. Sitona damage is very characteristic; adults chew C-shaped scallops out of leaf edges.

To monitor lucerne stands for sitona weevil use one of two approaches: 1. Stands that are thin, or have been grazed: look for signs of damage on leaves. Look around plants for weevils. You may need to keep still and wait for a minute or so until the weevils start moving around. 2. Hay crops: use a sweep net to sample. Take 10 sweeps and look for weevils. Repeat at a number of sites around the paddock. The distribution of sitona weevil may be quite patchy, with damage occurring in only part of the paddock.

Sitona weevil adults will feed actively through spring and early summer, becoming inactive in about mid December. These adults survive in sheltered sites over the summer, becoming active again in autumn when they feed on emerging medics, lucerne and other susceptible crops.

There are no established thresholds for sitona weevil. Heavy infestations in hay crops may warrant chemical control. Moderate levels of damage can be tolerated, given the short period of activity.

LAST BULLETIN NEXT WEEK Next week’s will be the last Budworm Bulletin for the season. It will contain a summary of moth activity and insect pest management research in pulses for 1997. Budworm Bulletin. Number 9. November 19, 1997 Budworm Bulletin Information on Native Budworm in Victorian Field Crops

The Budworm Watch program is supported by the Grains Research & Development Corporation

BULLETIN NUMBER 9. November 19, 1997 (3 PAGES) From Melina Miles & Matthew McCallum, VIDA Horsham. Ph (03) 53622 111, Fax (03) 53622 187 Julian Connellan, Swan Hill. Ph (03) 50324 461.

Pollfax access: Dial 1902 990 506 or 0055 10700 from your fax machine. Document No. 33301.

FINAL BUDWORM BULLETIN FOR 1997 This bulletin provides a summary of native budworm activity and some of the sampling that has been ongoing in the Wimmera and Mallee this season.

Below is a graph showing the pattern of moth flights in the Mallee and southern Mallee for 1997. The graph illustrates when the most significant moth activity occurred, during early to mid October. The pattern of flights was similar in both the Wimmera and Mallee. It is not possible to distinguish 480 the individual trap catches from 460 Data for traps at: this graph, but it provides an 440 Warracknabeal 420 Brim overview of the activity during 400 Birchip the season. 380 Dumosa Manangatang Overall moth numbers have been 360 Goschen 340 Mallan, NSW average to below average. These 320 low numbers are probably a 300 result of low populations of 280 native budworm in the source 260 areas (inland Australia) and the 240 absence of winds suitable for 220 migration. This season we have 200 Moths in trap in Moths not had the frequent, strong 180 160 frontal systems moving across 140 the state. Consequently the pre- 120 frontal northerlies which, are the 100 principal means of budworm 80 migration, have not eventuated. 60 40 The outlook for 1998 will again 20 depend on the conditions in 0 inland Australia. Good winter rains generate substantial plant growth on which large native 1-Oct 1-Nov 1-Sep 10-Oct 30-Oct 20-Oct 10-Nov 10-Sep 20-Sep budworm populations breed. It Date (1997) will be June-July before any predictions can be made about 1998.

Budworm Bulletin No.9, November 19, 1997 Moths, grubs and pod damage

During the 1997 season, a number of crops have been monitored regularly to track the development of budworm populations. The crops we selected had pheromone traps in them, and on a weekly basis from flowering on, estimates of egg numbers, larval numbers and pod damage were made.

The aim of the work was to get a handle on the relationship between moth trap catches and subsequent budworm caterpillar numbers, and to investigate the relationship between caterpillar numbers and crop damage.

The two graphs below illustrate the results from two of the paddocks monitored.

9.2% 6.00 Peas - Swan Hill 3.5% s 140 p Interpreting the graphs 5.00 120 The number of moths caught in

100 4.00 er 10 swee pheromone traps during the season is p represented by the continuous line, 80 with the numbers presented on the left 3.00 hand side of the graph. 60 Moths trapped Moths 2.00 The average number of larvae in the 40 crops is shown by the bars. The crops e number of larvae 0% 1.00 g were sampled 2-3 times with sweep 20

vera nets, with around 75-100 sets of 10 A 0 0.00 sweeps taken from each paddock.

The percentage of pod damage 1-Oct 3-Sep 17-Oct 10-Oct 23-Oct 10-Sep 20-Sep recorded is indicated above the bar that represents larval numbers. At each sampling date 100-500 pods were 450 0.3 2.6% s collected from each paddock and Beans - Dooen 1.4% p 400 inspected for damage.

350 In each paddock a follow up pod

0.2 er 10 swee collection was made after the crops 300 p could no longer be swept. This final 250 damage figure is presented by a lone 0% 200 % figure in the top right corner of each graph. Moths trapped Moths 0.1 150 What this simple sampling exercise

100 larvae of e number g illustrates is how the population of 50

vera larvae develops in the crops following A 0 0.0 the significant moth flights. It reinforces the importance of identifying major flights of moths as an indicator 1-Oct 3-Sep 1-Nov 6-Nov 10-Oct 17-Oct 23-Oct 10-Sep 20-Sep 10-Nov of likely larval infestations later in the season.

The increase in pod damage over time is the result of both an increase in larval numbers, and a the progression of larvae from early to late instars. The presence of larvae earlier in the season, without pod damage, is typical of a population of early instar larvae. As these larvae mature they begin burrowing into pods. There was some early pod burrowing this year following the warm few days in late October.

Etiella and lentils

2 Budworm Bulletin No.9, November 19, 1997 Etiella numbers in light traps in lentil crops continue to be low. No etiella larvae have been found in hundreds of lentil pods examined from crops in the Wimmera. One etiella larva was found in a pea pod from Brim (out of around 400 pods examined). Therefore, no recommendations to control etiella have been made. The appearance of moths in light traps coincided with much of the spraying for budworm that occurred in the Wimmera, so there may have been incidental control. It will not be until grain has been harvested that it will be possible to tell how severe etiella infestations have been this year.

Budworm Watchers Thanks again to all the trap operators who provided valuable information throughout the season. Your efforts are appreciated greatly. The data collected is used locally for distribution through the Bulletin and other media. It is also used by University of Queensland scientists who are working on a model to predict flights of native budworm using weather data. They are using the trap data collected in Victoria to test the accuracy of their model. It is possible, if the model proves to be reliable, that the model may be used to provide information on when significant flights of moths are likely to invade - doing away with the need for labour intensive pheromone traps?..perhaps.

If you are interested in the migration model it is possible to have a look at the predictions for 1997 and past season via the internet. There is information on flights into Birchip based on data generated at this and other Mallee/Wimmera sites. It is also possible to play with the model, looking at where moths that arrived in Victoria on certain nights may have originated.

The internet address is: http://www.fassbinder.ento.ctpm.uq.edu.au/forecast/migration/intro.html

Past issues of the Bulletin A reminder that previous issues of the 1997 Budworm Bulletin are available on pollfax. The current bulletin is available as document number 33301 Bulletin number 1 as 33311 Bulletin number 2 as 33312...etc

Budworm Watch in 1998. The Budworm Watch program will be running again in 1998, starting in August-September.

We would appreciate your comments on the information provided through the Bulletin in 1997, and suggestions for 1998.