Doses Of Methoprene Research Articles

Effects of different hormones as dietary supplements on biological characteristics of Coccinella septempunctata L.

AbstractWhen Coccinella septempunctata L. was fed on an artificial diet, development was prolonged and survival and reproduction were decreased, thus negatively affecting population growth. Juvenile hormone and moulting hormones are important factors in insect reproduction and development. This study aims to screen out the optimal hormones that can solve the problems such as slow population growth of the C. septempunctata during mass rearing, thus improving their effectiveness as a biological control agent. The effects of juvenile hormone analogues and moulting hormones on C. septempunctata larval growth and adult reproduction were investigated by supplementing an artificial diet with different doses of methoprene, kinoprene, juvenile hormone Ш, fenoxycarb and 20‐hydroxyecdysone. Multiple parameters were measured for C. septempunctata including development, survival, pupation, emergence, pre‐oviposition, fecundity and hatching rates. The addition of juvenile hormone analogues to the diet significantly lengthened larval development times and reduced pupation and emergence. Conversely, juvenile hormone analogues significantly shortened pre‐oviposition period, reduced survival and increased fecundity. The shortest pre‐oviposition period was 9.6 days, and the highest oviposition number was 578 eggs in response to 5 μL kinoprene. The highest hatching rate was 66% in 1.7 mg 20‐hydroxyecdysone treatment. The results of this study provide a theoretical basis for hormone selection and dosage in C. septempunctata artificial diets, thus enhancing the survival, pupation and emergence of larvae and improving the fecundity and hatching rate of ladybird adults.

Extended pre‐release holding with raspberry ketone and methoprene as supplements: Field performance of Bactrocera tryoni males

AbstractIn Sterile Insect Technique (SIT) programs, the released sterile insects must attain sexual maturity at an early adult age so that a large proportion survive to mature and contribute to reducing reproduction of pest populations. Previous field studies based on release of adult Queensland fruit fly, Bactrocera tryoni (Froggatt) (‘Q‐fly’), at 2 days of age found a significant increase in the recapture of mature male Q‐flies when they were provided methoprene or raspberry ketone (RK) before release. SIT for Q‐flies has subsequently adopted release at 5 days of age; there is now a contextual need to re‐assess the merit of methoprene and RK supplements. We assessed field abundance and dispersal of mature sterile male Q‐flies that had been held for 5 days on pre‐release standard diets of sugar and yeast hydrolysate (3:1) (control) with and without methoprene or RK supplements. Overall, the proportion of control‐ and RK‐treated flies recaptured was higher than the proportion of methoprene‐treated flies recaptured. We found no evidence that either methoprene or RK supplements yielded improvements over the control diet alone concerning abundance and dispersal of the male Q‐flies. Laboratory studies indicate that while the doses of methoprene (control + methoprene at 0.05% or 0.5%) and RK (control + RK at 1.25% or 5%) used in field releases at 2 days of age did not affect male longevity when sustenance was provided, these doses resulted in reduced longevity when no sustenance was provided. Furthermore, all doses of methoprene and RK used in field releases at 5 days of age reduced male longevity regardless of sustenance. At 5 days of age, the flies are already in an advanced state of maturity when released and in this context, it appears that additional pre‐release treatments of methoprene and RK provide no further improvement and may even be detrimental when nutrition is scarce.

Toxicity And Physiological Activity of Methoprene, A Juvenile Hormone Analog, Against Development and Metamorphosis of The Grey Flesh Fly, Parasarcophaga argyrostoma (Robineau- Desvoidy)(Diptera: Sarcophagidae).

The grey flesh fly Parasarcophaga argyrostoma plays a role in human cutaneous wounds and eye myiasis and it is also known as parasitoid of various animals. The present study aimed to investigate the efficacy of Methoprene on survival, development and metamorphosis of this fly species. Five dose levels (10.0, 5.0, 1.0, 0.1 and 0.01µg/larva) of Methoprene was topically applied onto the early last instar larvae and prepupae. Methoprene exhibited larvicidal, pupicidal and adulticidal activities against P. argyrostoma. LD50 values were found 0.155 and 0.258 µg/insect after topical treatment of early last instar larvae and prepupae, respectively. The maximal body weight of treated larvae was considerably decreased. The duration of treated larvae was prolonged. The coefficient of growth of treated larvae was depressed. The pupal duration was remarkably prolonged. Some larval-pupal intermediates had been produced, only at the higher two doses. Topical treatment of prepupae only with the lower two doses induced a state of 'permanent prepupae'. The treated last instar larvae pupated in regressed rate. The pupation rate was slightly regressed after topical treatment of prepupae only with the lower two doses. The adult emergence of flies was completely blocked after topical treatment of either the early last instar larvae or prepupae with the highest dose of Methoprene. At other dose levels, the adult eclosion of flies was partially blocked. Different percentages of deformed pupaeand adults were recorded.

STUDY OF QUANTITATIVE CHARACTERS BY SILKWORM LARVAE AFTER TOPICAL APPLICATION OF METHOPRENE AND FENOXYCARB

Juvenile hormone analogues have been tested as insect growth regulators in silkworm (Bombyx mori), seeking an increment of silk production. These chemical products, when applied in small or moderate rates, promote the extension of the last larval instar. In the cocoons and silk from 5th instar B. mori treated with selected doses of methoprene and fenoxycarb. Quantitative parameters like larval weight, silk gland weight , cocoon weight, cocoon shell weight, were determined. Methoprene and fenoxycarb influenced positively the duration of the fifth instar and the weight gain of the insects. Comparatively to the control lot, the increment on silk production was approximately 24% by the use of 1ng methoprene

Effects of Methoprene on Chemical Communication, Courtship, and Oviposition in the Cabbage Looper (Lepidoptera: Noctuidae)

Adult cabbage looper, Trichoplusia ni (Hubner), moths were topically treated with methoprene to determine the effect of this juvenile hormone mimic on the sequence of reproductive activities. Treatment of adults with a dose of methoprene that interferes with larval development did not alter pheromone production or calling behavior of females, the anemotactic flight of males, or courtship behavior. However, oviposition by virgin and mated females increased significantly after treatment with methoprene. In addition, hatch-ability of eggs laid by mated females was significantly reduced when they were treated with methoprene.