James A. Silva

Residual effect of calcium silicate on Ph, phosphorus, and aluminum in a tropical soil profile

Abstract The distribution of soil pH, extractable soil P, and AI was studied during 5 years of cropping in the soil profiles of a gibbsihumox soil at one P level (280 kg P/ha), three Si levels (0,830, and 1.660 kg Si/ha), and three pH levels (5.5, 6.0, and 6.5). The effect of residual Si on increased P availability was evident only in the surface layer. There was no indication of P movement below 15-cm depth as very little P was detected in the 15- to 30-cm soil layers. The differential in the observed soil pH due to initially adjusted pH values was persistent during the length of experiment as the soil pH values were higher at pH 6.5 treatment than that at pH 5.5 or 6.0 to a depth of 90 cm. The soil pH values were lower in the 15- to 30-cm soil depth than that in the 0- to 15-cm depth. This phenomenon was observed at all pH treatments at the 27-, 40-, and 56-month sampling and demonstrated that more of the liming material reacted with the surface soil and less moved to subsurface layer. The high A1 conce...

Species‐, age‐, and sex‐specific susceptibility of Mediterranean fruit flies 1 , oriental fruit flies 1 , and melon flies 1 to carbon dioxide 2

Abstract The 3 tephritids in Hawaii of economic importance, namely the Mediterranean fruit fly (medfly), Ceratltls capltata (Wiedemann), the oriental fruit fly, Dacus dorsalis Hendel, and the melon fly, D. cucurbitae Coquillett, showed marked differences in species‐, age‐, and sex‐specific susceptibilities to CO2 anesthetization. Mortalities for medflies exposed to CO2 increased more with time than did mortalities for the other 2 species. Older medflies and oriental fruit flies were more susceptible to CO2 exposure than were younger flies. Female medflies and oriental fruit flies were generally affected more by CO2 exposure than were males. Melon files were the least affected of the tested species by anesthetization with CO2.

Optimal Formulations with Phantolid for Extending the Duration of Effectiveness of Trimedlure and Methyl (E)-6-Nonenoate as Attractants to Male Mediterranean Fruit Flies

In 1976 we reported1 that certain perfume fixatives controlled the release of trimedlure,2 an attractant of male Mediterranean fruit flies, Ceratitis capitata (Wiedemann), and thereby enhanced the duration of effectiveness of this lure. The perfume fixatives were evaluated in an olfactometer stocked with laboratory massreared flies, and included tonalid, musk R-1, ambrettozone, galaxolide, astrotone, hibiscolide, phantolid, and musk BRB.

Species‐specific enhancement of oviposition of female oriental fruit flies 1 , melon flies 1 , and mediterranean fruit flies 1 when mated with normal males or with males sexually sterilized by tepa or gamma irradiation 2

Abstract Laboratory‐reared virgin females of 3 species of Tephritidae oviposited significantly fewer eggs than similar previously mated females. Melon flies, Dacus cucurbitae Coquillett, were most affected (3.0X more eggs for mated females), and Mediterranean fruit flies, Ceratitis capitata (Wiedemann), were least affected; oriental fruit flies, D. dorsalis Hendel, were in between. Numbers of eggs laid by females mated with males treated either with tepa in drinking water or with gamma irradiation were not significantly different from those laid by females mated with untreated males. Thus, mating per se was important in enhancing oviposition regardless of the fertility of the males.