Abstract
BACKGROUD: The red spider mite Tetranychus urticae is known as a worldwide pest in cassava production which can caused serious economic losses. Because no threshold levels are established for T. urticae in cassava cropping, many growers in China are applying excessive chemical applications per cassava cropping period. This is not only expensive, but also results in lower yields because of severe leaf damage and development of resistance. This study aims to develop an immediate threshold level for T. urticae control which could be determined in the laboratory and fit the field application requirements. RESULTS: The mite density of 25 mites/leaf was the threshold which caused significant decrease of photosynthetic pigment contents and protective enzyme activities in cassava leaves in the laboratory. Moreover, 25 mites/leaf was also the threshold density which resulted in significantly lower leaf damage and higher yield levels compared with a higher level of mites/leaf where calendar sprays were used. CONCLUSION: The mite density threshold that brought about significant physiological and biochemical changes in the laboratory basically coincided with the threshold that resulted in significant yield loss in the field. It is therefore concluded that the optimum threshold acaricide spray for T. urticae on cassava is 25 mites/leaf. © 2019 Society of Chemical Industry.
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Claims 5
Claim · model-written summary
A density of 25 mites/leaf was the threshold causing significant decrease of photosynthetic pigment contents and protective enzyme activities in cassava leaves in the laboratory.
- Taxon
- cassava
Manihot esculentae0 - Organ / stage
- leavese0
- Treatment
- mite density of 25 mites/leafe0
- Interactor
- mitee0pest
- Outcome
- photosynthetic pigment contents and protective enzyme activitiese0
- Direction
- decreasee0
- Setting
- the laboratorye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mite density of 25 mites/leaf was the threshold which caused significant decrease of photosynthetic pigment contents and protective enzyme activities in cassava leaves in the laboratory”
Claim · model-written summary
At the 25 mites/leaf threshold, leaf damage was significantly lower than at a higher mite level with calendar sprays.
- Taxon
- cassavaManihot esculentat0
- Treatment
- 25 mites/leafe0
- Interactor
- mitese0pest
- Outcome
- leaf damagee0
- Direction
- lowere0
- Comparator
- a higher level of mites/leaf where calendar sprays were usede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“25 mites/leaf was also the threshold density which resulted in significantly lower leaf damage and higher yield levels compared with a higher level of mites/leaf where calendar sprays were used”
t0“cassava”
Claim · model-written summary
At the 25 mites/leaf threshold, yield levels were significantly higher than at a higher mite level with calendar sprays.
- Taxon
- cassavaManihot esculentat0
- Treatment
- 25 mites/leafe0
- Interactor
- mitese0pest
- Outcome
- yield levelse0
- Direction
- highere0
- Comparator
- a higher level of mites/leaf where calendar sprays were usede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“25 mites/leaf was also the threshold density which resulted in significantly lower leaf damage and higher yield levels compared with a higher level of mites/leaf where calendar sprays were used”
t0“cassava”
Claim · model-written summary
The mite density threshold causing laboratory physiological and biochemical changes basically coincided with the threshold causing significant field yield loss.
- Taxon
- cassavaManihot esculentat0
- Outcome
- significant yield loss in the fielde0
- Qualifier
- basically coincidede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mite density threshold that brought about significant physiological and biochemical changes in the laboratory basically coincided with the threshold that resulted in significant yield loss in the field”
t0“cassava”
Claim · model-written summary
The authors conclude the optimum threshold for acaricide spray against T. urticae on cassava is 25 mites/leaf.
- Taxon
- cassavaManihot esculentae0
- Interactor
- T. urticae
.jpg?width=60)
Tetranychus urticaee0pest - Outcome
- optimum threshold acaricide spraye0
- Value
- 25 mites/leafe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“the optimum threshold acaricide spray for T. urticae on cassava is 25 mites/leaf”