Are aphid mean relative growth rate and intrinsic rate of increase likely to show a correlation in plant resistance studies?

1995 ◽  
Vol 119 (1-5) ◽  
pp. 405-409 ◽  
Author(s):  
E. Wojciechowicz-Zytko ◽  
H. F. Emden
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Plant Resistance ◽  
Intrinsic Rate ◽  
Intrinsic Rate Of Increase ◽  
Relative Growth ◽  
Rate Of Increase ◽  
Mean Relative Growth Rate

scholarly journals THE EFFECT OF MID-SEASON VINE REMOVAL ON THE GROWTH OF FIVE SWEETPOTATO (IPOMOEA BATATAS L.) CULTIVARS

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 266E-266
Author(s):  
Victor A. Kahn ◽  
C. Stevens ◽  
T. Mafolo ◽  
C. Bonsi ◽  
J.Y. Lu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Assimilation Rate ◽  
Marketable Yield ◽  
Relative Growth ◽  
Crop Growth Rate ◽  
Mean Relative Growth Rate ◽  
The Mean ◽  
Net Assimilation

TU-82-155 and `Georgia-Jet' early maturing. `Carver II', TU-1892 and `Rojo-Blanco' late maturing sweetpotato, cultivars were evaluated in the field for 0.20 and 40% vine removal (VR) at 8 wk after transplanting. Parameters measured were: leaf area index (LAI) recovery, net assimilation rate, foliage crop growth rate (FCGR), storage roots crop growth rate (RCGR). alpha a (the mean relative growth rate in dry wt to the mean relative growth rate in leaf area over a time interval) or the partitioning of assimilates, total and marketable yield. A split. splitplot design was used and plants were sampled at 3 and 8 wk following VR. Except for TU-82-155 all cultivars showed significant LAI recovery above the control at 3 and 8 wk after vine removal when 20% of the vines were removed while at the 40% VR, only 'Georgia-Jet'. TU-1892 and 'Carver II' showed significant increases in LAI for the same periods. Net assimilation rate showed significant interactions while FCGR was not significantly affected by either 20 or 40 VR compared to the control at 3 or 8 wk after VR. RCGR was significantly affected by both levels of VR at 3 and 8 wk after VR and surplus assimilates (alpha a) showed significant interactions between cultivars and % VR. Told yield declined for all cultivars irrespective to maturity groups with the sharpest decrease being at the 20% VR. All cultivars except TU-82-155 showed a decrease in marketable yield, the increase in marketable yield of TU-82-155 was due to a lower non-marketable yield.

Growth Responses of Tanoak Sprout Clumps to Thinning

1994 ◽  
Vol 9 (4) ◽  
pp. 101-105 ◽  
Author(s):  
Timothy B. Harrington
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Growth Responses ◽  
Relative Growth ◽  
Vegetation Height ◽  
Crown Width ◽  
Lithocarpus Densiflorus ◽  
Mean Relative Growth Rate ◽  
Relative Cover ◽  
Second Year

Abstract At two sites in southwestern Oregon, stands of tanoak (Lithocarpus densiflorus) were thinned in the second year after sprouting (1983) to create relative covers of 25, 50, or 100% of that for unthinned stands. At one site, relative covers were replicated with and without suppression of understory vegetation. Height, crown width and dominant-stem diameter were measured annually on each of 135 sprout clumps of tanoak from 1983-1988. Reductions in relative cover caused a proportionate increase in mean relative growth rate (RGR) of tanoak; however, the effect of understory suppression was not consistent. Increases in RGR of individual clumps from thinning were considerably greater for crown width (73% and 43% for large and small clumps, respectively) than for height (28% and 22%). Predicted crown width of tanoak 6 yr after thinning and understory suppression was up to 46% greater than that of clumps in untreated stands. West. J. Appl. For. 9(4):101-105.

Effect of host plants on life history traits of Phenacoccus solenopsis (Homoptera: Pseudococcidae)

2018 ◽  
Vol 38 (04) ◽  
pp. 387-393 ◽  
Author(s):  
Abdul Manan Dogar ◽  
Mahmood Ayyaz ◽  
Naeem Abbas ◽  
Sarfraz Ali Shad ◽  
Afifa Naeem
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Host Plants ◽  
Development Time ◽  
The Other ◽  
Female Adult ◽  
Phenacoccus Solenopsis ◽  
Relative Growth ◽  
Male And Female ◽  
Mean Relative Growth Rate

AbstractCotton mealybug,Phenacoccus solenopsisTinsley is an important polyphagous insect pest and causes severe losses to different crops worldwide. In the current study, we investigated the effect of different host plants, such asCaesalpinia pulcherrima,Plumeria rubra, Anthurium andraeanum, Jasminum sambac, andHibiscus rosasinensis, on the biological parameters ofP. solenopsis. The survival rate from crawler to adult, female nymphal duration, development time from crawler to female adult, and female adult weight were significantly different on the different hosts. Male nymphal duration, development time from crawler to male adult, pupal weight, emergence rate of male adults, and mean relative growth rate for male were similar on all the tested host plants. Pupal duration and generation time of male and female onH. rosasinensiswere significantly shorter than on the other hosts. Adult male and femaleP. solenopsislongevity was significantly shorter onH. rosasinensiscompared to other hosts. The fecundity was lower onC. pulcherrimaandA. andraeanumand hatchability was lower onC. pulcherrimathan on the other hosts. The net reproductive rate, the intrinsic rate of natural increase, and biotic potential and mean relative growth rate for female ofP. solenopsiswere significantly different on the tested hosts. Our results point to the role of host plants in increasing the populations ofP. solenopsisand could help to design cultural management strategies.

scholarly journals What mechanisms are involved in cabbage-clover intercropping and a further proof of the 'host plant quality' hypothesis

2000 ◽  
Vol 6 (4) ◽  
Author(s):  
Z. Seress ◽  
R. G. McKinlay ◽  
B. Pénzes ◽  
K. Sezák
Keyword(s):  
Growth Rate ◽  
Host Plant ◽  
Relative Growth Rate ◽  
Field Trials ◽  
Plant Quality ◽  
Host Plant Quality ◽  
Relative Growth ◽  
Mean Relative Growth Rate ◽  
The Mean ◽  
Aphid Populations

Over 10 years of field trials show reductions of most of the pests in Brassicas undersown by clover. The pest-reducing effects are due to the 'appropriate / inappropriate landings' hypothesis (Finch, 1996), and the 'host plant quality' hypothesis (Theunissen, 1994). To find out the mechanisms within the 'host plant quality' hypothesis in the most promising intercropping (collards undersown by clover) glasshouse experiments were conducted to see whether intercropping influences the mean relative growth rate, fecundity and time of maturity of Myzus persicae (Sulzer) (Homoptera: Aphididae) a common pest of Brassicas. The treatment modelling intercropping showed the smallest mean relative growth rate, delayed the maturity and slowed down the growth of cabbages. The treatment modelling monocropping showed the highest mean relative growth rate and the maturity was reached earlier. These results may indicate that intercropping delays the growth of settled aphid populations, giving another proof that in the case of clover undersown cabbages the 'host plant quality' hypothesis is likely to be acting. The differences between treatments where the roots of clover and cabbages were separated and allowed to grow together suggest that the effect is via the roots by competition.  

Influence of temperature on the development and reproduction of Cinara cedri (Hemiptera: Aphidoidea: Lachninae)

2021 ◽  
pp. 1-6
Author(s):  
Yingchao Ji ◽  
Guohua Li ◽  
Chenggang Zhou ◽  
Shuyan Yin
Keyword(s):  
Intrinsic Rate ◽  
Intrinsic Rate Of Increase ◽  
Threshold Temperature ◽  
Reproduction Rate ◽  
Cedrus Deodara ◽  
Developmental Threshold ◽  
Factors Affecting ◽  
Rate Of Increase ◽  
Influence Of Temperature On ◽  
Development Duration

Abstract Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.

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