Effect of age on the reproductive fitness of <i>Platygaster demades</i> an egg parasitoid of apple leafcurling midge

Platygaster demades is an egg parasitoid of the apple leafcurling midge (ALCM) Dasineura mali Each P demades female carries a mean preovipositional load of 1380 263 eggs Females fed with buckwheat nectar lived a maximum of 10 weeks at 15C The agedependent reproduction of female P demades was determined by a laboratory experiment at room temperature ALCM eggs on apple shoots were exposed to 1 2 4 8 and 10weekold individual P demades females and ALCM larvae that emerged from the parasitised eggs were reared on fresh apple shoots and allowed to pupate on a layer of moist soil The numbers and sex of adult P demades that emerged from the ALCM pupae were recorded Older females (8 and 10 weeks old) were able to locate and parasitise host eggs and produced as many offspring as younger females The implication of the results in terms of the reproductive fitness of P demades is discussed</jats:p

Influence of temperature and flowers on longevity of adult &lt;i&gt;Platygaster demades&lt;/i&gt;

Failure by Platygaster demades to provide effective biological control of apple leaf curling midge (ALCM) may be because the second spring generation of the parasitoid is asynchronous with that of its host Asynchrony may result from relatively slow development of P demades at low temperatures in spring In laboratory experiments adult female P demades provided with honeyagar diet lived significantly longer at 11deg;C (479 28 days) than at 19deg;C (194 days) and 27deg;C (27 days) Platygaster demades were provided with fresh flowers of Anethum graveolens (dill) Coriander sativam (coriander) Fagopyrum esculentum (buckwheat) Lobularia maritime (alyssum) Phacelia tanacetifolia (purple tansy) and Sinapis alba (white mustard) Both sexes lived longest (and comparably to the honeyagar diet) when provided with buckwheat flowers The possibilities for using buckwheat in apple orchards to prolong the first generation of P demades sufficiently to synchronise with the second generation population of ALCM are discussed</jats:p

Diel asynchrony in reproductive behaviour of &lt;i&gt;Diaeretiella rapae&lt;/i&gt; (MIntosh) (Hymenoptera Aphidiidae)

Diaeretiella rapae is an important parasitoid of cabbage aphid Diel variation in emergence mating and oviposition of D rapae was studied in the laboratory to understand the biology and behaviour of the parasitoid The emergence of the parasitoid was recorded hourly in two bioassay rooms set up at 22 2C with 16 h photoperiod from 08002400 hours or from 18001000 hours Greatest emergence was found during the early photophase The parasitoids that emerged during the scotophase did not mate until the following photophase Unmated females that emerged during the scotophase had a lower incidence of host attack and oviposition during the dark However the parasitoids became active and had a greater incidence of mating and oviposition when they were brought into the light even during the scotophase This research suggests that light triggers parasitoid activity and that the parasitoids lose their reproductive fitness if they emerge in the scotophase</jats:p

Survival and reproduction of Liberibacterinfected tomato potato psyllid reared under cold environmental conditions

The tomato potato psyllid (TPP Bactericera cockerelli) survives on volunteer potatoes growing in frostfree areas in winter in the Auckland region and therefore could transmit Candidatus Liberibacter solanacearum (Lso) to commercial crops The survival and oviposition of laboratoryreared Lsoinfected TPP were tested under four selected environmental conditions 1212 h lightdark at 10C; 1311 h lightdark at 12C; 1410 h lightdark at 14C; and 159 h lightdark at 16C on excised leaves from volunteer potatoes (grown in the field during winter) and tomato (grown in the glasshouse) One hundred pairs of adult TPP (10 pairs/leaf) were tested on either potato or tomato in each environmental condition for 7 days Survival of females on potato or tomato was not significantly different between photoperiod but remained unhatched in all tested temperatures Results revealed that Lsoinfected TPP could feed (as indicated by excretory droplets) oviposit and survive on volunteer potatoes in Auckland winterlike conditions and potentially transmit Lso to crops grown in these cooler months</jats:p

Evaluation of host testing by comparing ingestion and settling behaviours

The electrical penetration graph (EPG) technique is being developed for rapid assessment of host range of potential xylem feeding invaders in New Zealand Stylet penetration behaviours of adult spittle bug Carystoterpa fingens were monitored for 12 h on grape lemon apple and kiwifruit plants using EPG A multiplechoice test of all four plant species was conducted concurrently with the EPG tests for comparison In EPG tests the longest probing and ingestion periods were recorded on grape and lemon while the shortest probing and ingestion periods were recorded on apple Results for kiwifruit were intermediate and not significantly different from the other plant types In the multiplechoice tests more insects were found on grape and lemon than on apple and kiwifruit The similar ranking of the host plants in both multiplechoice and EPG tests suggests that EPG is a valid tool for rapidly assessing host feeding acceptance and preference</jats:p

Development of citrophilus mealybug (&lt;i&gt;Pseudococcus calceolariae&lt;/i&gt;) on grape roots

Pseudococcus calceolariae (Hemiptera Pseudococcidae) is a vector of Grapevine leafrollassociated virus 3 (GLRaV3) the most destructive virus disease affecting New Zealand grapevines Previous studies suggest that P calceolariae can survive on remnant vine roots for at least 12 months and these mealybugs could account for the spread of the disease in replanted vineyards A laboratory assay test was developed to observe the growth of P calceolariae on grape rootstock 3309 Clean root pieces were left on moist filter paper in Petri dishes for a week to encourage new growth before P calceolariae eggs (n15) were inoculated and held at 23C Recordings were made every 34 days of the survival and development from first instar until males emerged as adults and females started oviposition About 50 mortality was recorded during first and second instars and ca 30 developed into adult stages The development periods from first instar to adult males and females were 441 1 (n16) and 454 1 (n22) respectively This methodology is being developed to assess the relative resistance of grapevine rootstocks effects of contact insecticides and to understand GLRaV3 transmission from roots</jats:p