Abstract
Abstract Background Due to recent bans on the use of several soil insecticides and insecticidal seed coatings, soil-dwelling insect pests are increasingly difficult to manage. One example is the western corn rootworm ( Diabrotica virgifera virgifera , Coleoptera: Chrysomelidae), a serious root-feeder of maize ( Zea mays ). We investigated whether the less problematic botanical azadirachtin, widely used against above-ground insects, could become an option for the control of this soil insect pest. Methods Artificial diet-based bioassays were implemented under standard laboratory conditions to establish dose response curves for the pest larvae. Then, potted-plant experiments were implemented in greenhouse to assess feasibility and efficacy of a novel granular formulation of azadirachtin under more natural conditions and in relation to standard insecticides. Results Bioassays in three repetitions revealed a 3-day LD 50 of 22.3 µg azadirachtin/ml which corresponded to 0.45 µg/neonate of D. v. virgifera and a 5-day LD 50 of 19.3 µg/ml or 0.39 µg/first to second instar larva. No sublethal effects were observed. The three greenhouse experiments revealed that the currently proposed standard dose of a granular formulation of 38 g azadirachtin/hectare for in-furrow application at sowing is not enough to control D. v. virgifera or to prevent root damage. At 10× standard-dose total pest control was achieved as well as the prevention of most root damage. This was better than the efficacy achieved by cypermethrin-based granules and comparable to tefluthrin-granules, or thiamethoxam seed coatings. The ED 50 for suppressing larval populations were estimated at 92 g azadirachtin/ha, for preventing heavy root damage 52 g/ha and for preventing general root damage 220 g/ha. Conclusions There seems clear potential for the development of neem-based botanical soil insecticides for arable crops such as maize. They might become, if doses are increased and more soil insecticides phased out, a promising, safer solution as part of the integrated pest management toolkit against soil insects.
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Claims 13
Claim · model-written summary
Azadirachtin had a 3-day larval LD 50 of 22.3 µg azadirachtin/ml, corresponding to 0.45 µg/neonate.
- Interactor
- D. v. virgiferae0pest
- Outcome
- 3-day LD 50e0
- Value
- 22.3 µg azadirachtin/mle0
- Qualifier
- 0.45 µg/neonatee0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 3-day LD 50 of 22.3 µg azadirachtin/ml which corresponded to 0.45 µg/neonate of D. v. virgifera”
e1“maize ( Zea mays )”
Claim · model-written summary
Azadirachtin had a 5-day larval LD 50 of 19.3 µg/ml, corresponding to 0.39 µg/larva.
- Interactor
- D. v. virgiferae1pest
- Outcome
- 5-day LD 50e0
- Value
- 19.3 µg/mle0
- Qualifier
- 0.39 µg/first to second instar larvae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 5-day LD 50 of 19.3 µg/ml or 0.39 µg/first to second instar larva”
e1“of D. v. virgifera and a 5-day LD 50”
e2“maize ( Zea mays )”
Claim · model-written summary
No sublethal effects on rootworm larvae were observed.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No sublethal effects were observed”
e1“of D. v. virgifera and a 5-day LD 50”
e2“maize ( Zea mays )”
Claim · model-written summary
The standard granular azadirachtin dose did not control rootworm.
- Treatment
- 38 g azadirachtin/hectaree0
- Interactor
- D. v. virgiferae0pest
- Outcome
- control D. v. virgiferae0
- Direction
- not enoughe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the currently proposed standard dose of a granular formulation of 38 g azadirachtin/hectare for in-furrow application at sowing is not enough to control D. v. virgifera or to prevent root damage”
e1“maize ( Zea mays )”
Claim · model-written summary
The standard granular azadirachtin dose did not prevent maize root damage.
- Treatment
- 38 g azadirachtin/hectaree0
- Interactor
- D. v. virgiferae0pest
- Outcome
- root damagee0
- Direction
- not enoughe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the currently proposed standard dose of a granular formulation of 38 g azadirachtin/hectare for in-furrow application at sowing is not enough to control D. v. virgifera or to prevent root damage”
e1“maize ( Zea mays )”
Claim · model-written summary
At 10× the standard dose, azadirachtin achieved total pest control.
- Treatment
- 10× standard-dosee0
- Interactor
- D. v. virgiferae1pest
- Outcome
- total pest controle0
- Comparator
- standard-dosee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 10× standard-dose total pest control was achieved as well as the prevention of most root damage”
e1“control D. v. virgifera or to prevent root damage”
e2“maize ( Zea mays )”
Claim · model-written summary
At 10× the standard dose, azadirachtin prevented most root damage.
- Treatment
- 10× standard-dosee0
- Interactor
- D. v. virgiferae1pest
- Outcome
- prevention of most root damagee0
- Comparator
- standard-dosee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 10× standard-dose total pest control was achieved as well as the prevention of most root damage”
e1“control D. v. virgifera or to prevent root damage”
e2“maize ( Zea mays )”
Claim · model-written summary
Azadirachtin efficacy was better than cypermethrin granules.
- Treatment
- azadirachtine3
- Interactor
- D. v. virgiferae2pest
- Outcome
- efficacye0
- Direction
- bettere0
- Comparator
- cypermethrin-based granulese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This was better than the efficacy achieved by cypermethrin-based granules and comparable to tefluthrin-granules, or thiamethoxam seed coatings”
e1“maize ( Zea mays )”
e2“of D. v. virgifera and a 5-day LD 50”
e3“a 3-day LD 50 of 22.3 µg azadirachtin/ml which corresponded to 0.45 µg/neonate of D. v. virgifera”
Claim · model-written summary
Azadirachtin efficacy was comparable to tefluthrin granules.
- Treatment
- azadirachtine3
- Interactor
- D. v. virgiferae2pest
- Outcome
- efficacye0
- Direction
- comparablee0
- Comparator
- tefluthrin-granulese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This was better than the efficacy achieved by cypermethrin-based granules and comparable to tefluthrin-granules, or thiamethoxam seed coatings”
e1“maize ( Zea mays )”
e2“of D. v. virgifera and a 5-day LD 50”
e3“the less problematic botanical azadirachtin”
Claim · model-written summary
Azadirachtin efficacy was comparable to thiamethoxam seed coatings.
- Treatment
- azadirachtine3
- Interactor
- D. v. virgiferae2pest
- Outcome
- efficacye0
- Direction
- comparablee0
- Comparator
- thiamethoxam seed coatingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This was better than the efficacy achieved by cypermethrin-based granules and comparable to tefluthrin-granules, or thiamethoxam seed coatings”
e1“maize ( Zea mays )”
e2“of D. v. virgifera and a 5-day LD 50”
e3“the less problematic botanical azadirachtin”
Claim · model-written summary
The estimated ED 50 for suppressing larval populations was 92 g azadirachtin/ha.
- Interactor
- D. v. virgiferae1pest
- Outcome
- ED 50 for suppressing larval populationse0
- Value
- 92 g azadirachtin/hae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ED 50 for suppressing larval populations were estimated at 92 g azadirachtin/ha, for preventing heavy root damage 52 g/ha and for preventing general root damage 220 g/ha”
e1“control D. v. virgifera or to prevent root damage”
e2“maize ( Zea mays )”
Claim · model-written summary
The estimated ED 50 for preventing heavy root damage was 52 g/ha.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ED 50 for suppressing larval populations were estimated at 92 g azadirachtin/ha, for preventing heavy root damage 52 g/ha and for preventing general root damage 220 g/ha”
e1“control D. v. virgifera or to prevent root damage”
e2“maize ( Zea mays )”
Claim · model-written summary
The estimated ED 50 for preventing general root damage was 220 g/ha.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ED 50 for suppressing larval populations were estimated at 92 g azadirachtin/ha, for preventing heavy root damage 52 g/ha and for preventing general root damage 220 g/ha”
e1“control D. v. virgifera or to prevent root damage”
e2“maize ( Zea mays )”
The same questions in other papers
azadirachtin · pest · Zea mays (maize)Positive and negative results
1 paper in the same direction as this paper · 3 in the opposite direction
- positive
- positive
- positive
1 paper more in this group
See all 5 papers →azadirachtin · control · Zea mays (maize)Results agree
1 paper in the same direction as this paper
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.