Temperature Dependence for Survival, Development, and Reproduction of the Cactus Cochineal Dactylopius opuntiae (Cockerell)
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Regional Center of Agronomic Research of Settat, Tertiary Road 1406, At 5 Km from Settat, Settat 26400, Morocco
2
Plant Protection Department, National Institute of Agricultural Research, Ennasr, Rabat 10000, Morocco
*
Author to whom correspondence should be addressed.
Insects 2022, 13(5), 426; https://doi.org/10.3390/insects13050426
Submission received: 5 March 2022
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Revised: 25 March 2022
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Accepted: 30 March 2022
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Published: 30 April 2022
(This article belongs to the Topic Integrated Pest Management of Crops)
Simple Summary
Cactus is an important drought-tolerant crop that has very various beneficial uses. In Morocco, cactus is a perfectly appropriate crop for land rehabilitation in the arid and semi-arid regions. With little investment, it can produce important resources for human and animal nutrition and generate adequate revenues for farmers. Unfortunately, the sustainability of this extremely resilient ecosystem has become seriously threatened by the appearance of Dactylopius opuntiae (Hemiptera: Dactylopiidae). This cochineal which is specific to cacti, was introduced in Morocco in 2014. The aim of this study was to evaluate the effect of temperature on life cycle parameters of D. opuntiae at 20, 23, 26, 32, and 40 ± 1 °C, 65 ± 5% RH, and a photoperiod of 12L:8D. Temperatures ranging from 26 °C to 32 °C were appropriate for the survival, development, and reproduction of the scale insect. Parthenogenesis in females was not observed during our study. This study also showed that D. opuntiae females required a higher thermal constant (769.23 D°) than males (357.14 D°) to grow to the mature adult stage.
Abstract
The effect of temperature on Dactylopius opuntiae (Cockerell) life cycle parameters was evaluated at 20, 23, 26, 32, and 40 ± 1 °C, 65 ± 5% RH, and a photoperiod of 12 L:8 D. Temperatures ranging from 26 °C to 32 °C were suitable for survival, development, and reproduction of D. opuntiae. The total developmental time of females ranged from 94.23 d (20 °C) to 43.55 d (40 °C). The average development time of males from egg to death ranged from 26.97 days at 32 °C to 50.75 days at 20 °C. The probability that a newly laid egg would survive to the adult stage was highest at 26 °C and 32 °C (44–60%). The parthenogenesis in females was not observed during our study. The longest oviposition period was observed when the cochineal was reared at 32 °C (17.97 days), and the highest fecundity was observed at 32 °C (355.29 egg/female). The highest proportion of females (0.80) was observed at 40 °C. According to the age-stage-two-sex life table, the highest value of the intrinsic rate of natural increase (rm) was recorded at 32 °C. The lower developmental thresholds for the total pre-adult female and male and adult female and male stages, were 10.15, 12.21, 10.54, and 21.04 °C, respectively. Dactylopius opuntiae females needed a higher thermal constant (769.23 D°) than males (357.14 D°) to achieve their development and reach the mature adult stage. These findings will be useful for the development of an integrated pest management strategy for D. opuntiae.
